+1^
I have been using un-bleached coffee filters for what seems like forever. Cheap, sterile, and no lint. Personally, I would not use any cotton balls. Leaves fuzz and could be a ESD problem.
Yes. It's what most folks use if they don't use a specific cleaner like Arctic Silver Arcticlean.
Most people probably use pure isopropanol? No need for overpriced specific cleaning stuff, and the 70% stuff is just not quite as good.
@OP it's safe, but pure isopropanol would be better. The less pure stuff can leave a slight residue and potentially affect cooling a little afterwards.
I have to put my cpu in a new mobo and I need to clean the thermal paste. I only have 70% alcohol. Is this safe?
The only "problem" with 70% is that the extra water will take a while longer to evaporate. Quicker drying time is the main motivation for using more volatile solvents. Many PCB assembly plants use water-soluble flux for assembly and mostly water as the PCB cleaning solvent. Distilled water is also fine as long as you didn't spill salt or anything else water-soluble that can make it conductive on the board.