Just pure alcohol, not rubbing alcohol which is based on isopropyl but with water and other stuff added. I also use pure Etil and Metil alcohol, they are just as good.
Then you should be fine. Be sure to use "lint free" cloths or paper coffee filters when cleaning contact surfaces. You do not want to use Q-tips, paper towels, toilet paper, regular cloth rags or anything likely (known) to leave lint or particles behind. A piece of lint the thickness of a human hair is enough to completely screw up a CPU cooler mount job or delid paste.