Arctic Silver ArctiClean
 

If you are reading this then you have probably at one time or another
had to remove thermal interface material from a heatsink. You might
be taking the ineffective crap off of a stock heatsink or merely
reapplying it after swapping out a CPU. At any rate, cleaning thermal
grease is a royal pain. Nothing seems to cut through it and even if
something does, it usually leaves behind a residue that defeats the
entire point of using thermal grease. Well imagine if I told you that
I had a magic bottle of stuff that would eat through thermal grease
like a hot knife through butter and not leave a trace of itself behind
after wiping it off. Too good to be true you say? Well thanks to our
good friends at Arctic Silver that day is here.

Direct Link: http://www.gideontech.com/content/articles/282/1