Removal Instructions (From Hardware)
1. Arctic Silver thermal compound can easily be removed from hardware using the proper cleaners and tools. For general clean-up, a cloth or paper towel will work well. Intricate cleaning can be accomplished with Q-tip swabs. An old toothbrush can often get the compound out of crevices that other tools cannot reach.
The recommended cleaners are:
Use isopropyl alcohol or acetone (nail polish remover) and a bit of careful rubbing.
(If you use acetone, do a final cleaning with isopropyl alcohol.)
Use xylene based products (Goof Off, some carburetor cleaners and many brake cleaners.) or mineral spirits.
Maybe a combination of acetone and rubbing alcohol will get the job done if you don't want to go out and buy engine degreaser.