Tape Glue On Coins

Acetone will take most kinds of "sticky goo", including old tape residue, off any kind of metal.

Be aware that even if the treatment successfully removes all the actual goo, the coin could still bear the marks of being taped for so long - a "stripe" or "hole" in the toning where the tape used to sit.

Do a forum search for "acetone" to see some people's experience with it. Here are the usual warnings for working with acetone:
- it's highly flammable, so don't smoke, keep away from fires or ignition sources, etc.
- many people find the fumes have an unpleasant odour and can cause dizziness etc. in some people. Use outdoors or in well ventilated area.
- it's very, very good at depolymerizing and dissolving all sorts of things, not just tape residue, so keep it away from anything made of plastic, and don't spill it on a varnished or laminated surface.

Other organic solvents such as alcohol, methylated spirits, rubbing alcohol, xylene, kerosene etc. may also work, but acetone has been found to be the most effective.