Its okay to clean the thermal compound off of the cpu, just use a q-tip with rubbing alcohol to do so. Make sure that the q-tip isn't dripping with rubbing alcohol though, just moist enough to do the job. It might take you awhile with just rubbing alcohol, but you could also get Goo Gone from walmart and speed up the process a bit, but clean it with rubbing alcohol after goo gone. If you use Goo Gone, don't have the q-tip dripping wet as well.
Also go to a local computer shop, preferably one that builds computers and ask if you can have the black plastic cover that protects the pins on the CPU, just to make sure it arrives safely when you ship it.
