How to Remove Hot Glue (and Other Adhesives) from a Mineral, Crystal, or Fossil

glue how-to mounting removal

Introduction

Whether you are trying to remove a specimen from an old base in order to remount it, remove an unsightly blob of adhesive stuck to a specimen you just acquired, or simply want to know how you would go about undoing your own hot glue job before you start, we'll show you the techniques you need to do it safely. Just follow these 3  steps: identify, separate from base (if applicable), and remove from specimen.

Step 1: Identify your adhesive.

There are a variety of adhesives used, for better or worse, to attach minerals to bases in the position a collector thought it should be displayed in. Most commonly used are mineral tack (aka mineral putty, museum putty, and others), hot glue, white glue (aka Elmer's Glue, school glue) - usually only used for very small specimens and for affixing labels, wax (usually older specimens), various epoxies, and clear nail polish (usually for affixing labels). Knowing what you're up against is the first step in getting the goop off of your specimen.

-Mineral tack is a whitish gray putty that is non-drying and sticky, sort of like used chewing gum. Though inferior types may dry out and harden with age, you should be able to poke it with a paper clip and leave a mark. Very identifiable, only confused with wax, which will be somewhat translucent instead of opaque. 

-Wax is a clear to tan to gray, semi-translucent substance. Non-drying, will retain a paper clip mark. There are different types waxes used but most can be removed the same way.

-White glue dries as a clear shiny film, usually only 1-2 mm thick at most. Starts softening pretty rapidly in warm water, which is identifying and also the removal technique. If using to remove a previous collector's label (often a short combination of letters and numbers like CJD0001), consider leaving it if it will not harm your enjoyment of the specimen. Past labels can have a lot of historic, scientific, sentimental, and monetary value for many collectors, and the next owner of the specimen (as we are all but temporary caretakers of our minerals) may appreciate having the historic labels very much.

-Clear nail polish looks like white glue, but completely insoluble in water. Almost always only used for collection labels. See "White glue" section above for an argument for NOT removing such labels.

-Epoxies can be clear to yellow to gray in color, and opaque to transparent. They are usually thick, and hard as a rock. Brittle to only very slightly flexible.

-Hot glue is usually clear to gray, and may be bluish to yellow in tint, and is usually semi-translucent but may be nearly opaque or transparent. Firm but springy, and at least somewhat flexible.

Step 2: Separate the mineral from the base (not on a base? skip to Step 3!)

Once identified, the next step towards complete removal is separating the mineral from its stand. How you will do so depends on the adhesive you identified in step one. The most important thing to remember is patienceTake your time, and never use force.

-Mineral tack (difficulty: easy to moderate) very gently rock specimen back and forth, holding as close to the bottom of the specimen as possible. Mineral tack softens as it is worked, so slow movements will eventually produce results. If very hard, even a little bit of warmth helps a lot, such as letting the piece sit in the sun or a warm car for a little bit. Once separated, see step 3 for residue removal.

-Wax (difficulty: easy)  as long as the mineral isn't heat sensitive, the easiest way is to place the piece and its base in a pot of room-temperature water. Not cold, not hot, as you could shock and damage the crystals. Slowly heat the pot on the stove until the wax softens enough to separate. If stubborn or temperature sensitive, can be loosened with same technique as mineral tack.

-White glue (difficulty: easy) simply place in a large container with room temperature water until dissolved. The more water the better so the glue is diluted and doesn't form a film on your mineral when dried.

-Nail polish (difficulty: easy to moderate) Acetone (nail polish remover) will be needed. Avoid soaking, but rather paint it on with a brush, cotton swab, etc. Acetone won't harm nearly any mineral, but it will dissolve most glues used for repairs (whether you knew they were there or not), and will dissolve acrylic bases, which will coat your specimens in residue that will be difficult to remove. Be patient and careful.

-Epoxies (difficulty: very hard) most chemicals won't touch it, this will be mostly mechanical. If your specimen is resistant to temperature changes, you can try using alternating hot and cold to get it to pop free. Place the stand in the freezer for an hour, then immediately hit it with a hair blow dryer, then repeat. Try slowly wiggling it free as you would for mineral tack. Do not force if possible, be persistent instead. If this fails, a thin saw blade can be used to saw between the specimen and stand, or hold as close to the joint as possible and use force, and hope the specimen breaks near the joint. Putting the base side in a vise is helpful. Have a soft blanket on the ground to catch the specimen if you drop it.

-Hot glue (difficulty: easy to hard). Hot glue can be very quick and easy, but a lot depends on the type of hot glue that was used, how much was applied, the fragility of the mineral specimen, and the surface texture of the mineral it was applied to. There are many different tricks and techniques that will loosen its grip entirely, or at least substantially enough to peel it off without much force, but because there are so many variables, we will follow a few steps to ensure safe removal.

Method A) The smooth surface of most display stands means that a gentle rocking motion will often free an object from the stand without much effort. (If so, proceed to Step 3 for instructions on removing the remaining blob from the mineral or stand, depending on which side it stuck to). Do not force it! If you meet any resistance, or your object is extremely fragile to begin with, try Method B instead.

Method B) ***WARNING: destructive for all plastic stands, if trying to preserve the stand, skip to methods C, D, or E*** Acetone (nail polish remover) will dissolve hot glue and plastic bases quickly, so rather than soak in acetone, apply small amounts slowly with a cotton swab, or paint brush and slowly peel the glue blob back bit by bit to expose more of the contact area to acetone. Use care to avoid letting excess acetone drip back onto the mineral specimen, as the dissolved glue and plastic from the base will leave a stubborn residue. Nearly every mineral is acetone safe, unless they have been repaired with glue, and even then it can still be used if you avoid getting it on the repaired area. If mounted to a piece of actual glass, you can simply let it sit in a container of acetone up to the level of the glue for a few minutes until it peels off easily. 

Method C) If you want to preserve the base, or have other reasons for skipping method B, try this. Follow the exact procedure of method B but use rubbing (isopropyl) alcohol or denatured alcohol (ethanol) instead of acetone if you want to preserve the stand. It works better than water but much worse than acetone, but is far less destructive to plastic. Still, avoid getting it on any paint fill on a engraved stand (if present), and don't leave it soaking in alcohol. Acrylic is very slightly soluble in alcohol over time, and most paints will be rapidly attacked. 

Method D) A slower alternative to method C, but safe, convenient, and effective as it uses only water and time. Hot glue will very slowly absorb water, causing it to swell and soften, which aids in removal through method A. Place the stand in a sink or container of water up to the level of the glue (use distilled covering any deeper) for at least 12-24 hours. Method A should now work to remove it from the stand, and hopefully the specimen as well. If this didn't work, you can return to water for another 24 hours, but if that fails, more soaking is unlikely to help and you'll need to try method E.

Method E) If your specimen can handle temperature changes, putting it in the freezer for an hour might make it brittle enough for method A to work. An hour in a hot car or a few minutes under a blow dryer can also work the same way. You can also alternate the two for greater effect.

Step 3: Remove remaining adhesive from specimen

Once your specimen is finally free, we can remove the remaining residue from the specimen (and/or its base, if you wish to reuse the base).

-Mineral tack (difficulty: easy) The best thing to remove mineral tack is mineral tack! Simply pry what you can off, and use it to repeatedly dab at the remainder like a woodpecker until its all gone. Not all tacks remove as easily as ours, so you may need to be patient. Sometimes the same tack works the best, and sometimes you'll have more luck with fresh tack but keep at it and you should be able to get it all sooner or later.

-Wax (difficulty: moderate)  As long as the mineral isn't heat sensitive, the easiest way is to place the piece and its base in a pot of room-temperature water. Not cold, not hot, as you could shock and damage the crystals. Use a deep pot with several inches of water above the top of the specimen. Slowly heat the pot on the stove until the water boils gently, causing the wax to melt completely. Do not remove the specimen from the water yet! Turn off the burner and allow to cool completely, causing the wax to solidify. Once it's a solid, it will float and can be removed. If you remove the specimen prematurely, you'll have a thin layer of wax everywhere and have made your problem much worse. If you know what you're doing, a bit of wetting agent can be added to the water in the begging to get every bit of wax out of the mineral.

-White glue (difficulty: easy) simply place in a large container with room temperature water until dissolved. The more water the better so the glue is diluted and doesn't form a film on your mineral when dried. Rinse well.

-Nail polish (difficulty: easy) Acetone (nail polish remover) will be needed. Acetone won't harm nearly any mineral, but it will dissolve most glues used for repairs (whether you knew they were repaired or not) which will also coat your specimens in residue that will be difficult to remove. So be careful or apply with a cloth, swab, or brush to just the area of nail polish.

-Epoxies (difficulty: very hard). You'll need patience. Carefully pick and pry with dental tools, use a dremel with fine carving bits, or a micro sandblaster. This will be about care and endurance to clean it bit by bit. For valuable specimens, do not attempt, but rather recruit a professional.

-Hot glue (difficulty: easy to hard). Hot glue removal can be very quick and easy, but a lot depends on the type of hot glue that was used, how much was applied, the fragility of the mineral specimen, and the surface texture of the mineral it was applied to. If hot glue is stuck to the stand, simply peel it off with your fingernail. You can put it in the freezer or soak in warm water if it won't come off, but it really should pop off the smooth stand pretty easily. If it is stuck to the object then use the first method in the following list that is safe for your object:

Method A) Simply peel it off with your finger. Smooth specimens, and those glued to the matrix with a powdery or fine-grained texture should peel off safely without much effort. Use caution. If you meet any resistance, or your object is extremely fragile to begin with, go for Method B instead.

Method B) Acetone (nail polish remover) will dissolve hot glue, so rather than soak in acetone, try applying amounts around the edge of the glue blob with a cotton swab or paint brush and slowly peel the glue blob back bit by bit to expose more of the contact area to acetone. Be patient, and keep the specimen upright to avoid letting excess acetone drip back onto the mineral specimen, as the dissolved glue can leave a stubborn residue. Nearly every mineral is acetone safe, unless they have been repaired with glue, and even then it can still be used if you avoid getting it on the repaired area. Depending the piece and your experience, you might be able to soak, but avoid soaking anything above the glue line for residue reasons.

Method C) A less effective but fair alternative to method B. Follow the exact procedure of method B but use rubbing (isopropyl) alcohol or denatured alcohol (ethanol) instead of acetone. It works better than water but much worse than acetone and neither will harm most minerals.

Method D) A slower alternative to method C, but safe, convenient, and effective as it uses only water and time. Hot glue will very slowly absorb water, causing it to swell and soften, which aids in removal through method A. Soak the mineral for at least 12-24 hours in distilled water. Use distilled to avoid residues. Method A should now work to remove it from the stand, and hopefully the specimen as well. If this didn't work, you can return to water for another 24 hours, but if that fails, more soaking is unlikely to help and you'll need to try method E.

Method E) If your specimen can handle temperature changes, putting it in the freezer for an hour might make it brittle enough for method A to work. An hour in a hot car or a few minutes under a blow dryer can also work the same way. You can also alternate the two for greater effect.

Conclusion

Hopefully the methods above worked for you! If so, we'd love to hear your success stories. Or maybe you're stuck or have questions ? We're here to help!  We can either give advice, remove your adhesives for you, or point you to a lab that can.

If you have other tips, tricks, or pitfalls not mentioned here, or have a critique of our methods, please share and we'll update the list for everyone's benefit! 


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