CPU cleaning?

I wanted to replace the thermal paste on my laptop and now wanted to ask if I should clean the copper cooler (the area for the CPU) with nitro thinner or benzine.

I would not say neither.

A soft cloth with a drop of water is enough.

You can take both

You can do both. Doesn't need much.

I always use normal disinfectant wipes for cleaning. They do not drip, do not smear with thermal paste, the alcohol evaporates on its own and they do not cost much.

But a normal cloth / Zewa is also sufficient. I would not necessarily use water, and if only really very little.

For such things you should take something that evaporates as residue-free as possible. Isopropanol offers e.g. At.