Use Isopropyl Alchohol (99% $3.00 at Drugstore) and Q-tips seem to scrub well. Also clean whatever your using to apply with alchohol first (any oil/dirt/lint bad).
I have used a drop of dish soap and a drop of water to scrub very thick white paste off! It won't hurt as long as you clean it all off after with something like alchohol. Just don't do this while CPU in computer