Before it cures:
To remove silicone before it is cured, use a putty knife to remove any of the uncured paste. Wipe the area clean with isopropyl alcohol to remove any leftover residue.
After it is cured:
First you should mechanically remove as much of the silicone as you can with either a knife or a razor. A solvent can them be used to remove any oily residue or any remaining silicone. It may be necessary to soak the silicone in a solvent overnight to break it down.
Below is a list of solvents in the order of aggressiveness in attacking the silicone:
· Paint thinner (mineral spirits)
· Methylene chloride.
When using solvents, as with any material, proper safety precautions should be observed.