How to remove thermal paste

[Sauhta]

Can I use water? Or can I just do it with nothing at all.

 

[coozie7]

Do not use water, it'll have no effect, if you need to use any type of solvent to soften the stuff pure alcohol is the usual weapon of choice-Isopropyl Alcohol ( rubbing alcohol ) is cheap and readily available.
If it's not hardened too much just a kitchen paper towel will do the job but do be careful when taking the stuff off the CPU, some pastes are electrically conductive, so keeping it away from the pins and socket is essential.