How to remove Black cooling paste on IC?
It seems to be some kind of thermal glue.

I removed it with (which I think was a lot) acetone and after a few attempts I saw some signs of a writing. It's an L293D.

In case someone else has this problem:
It's best if you use some towel to soak in acetone (just a small piece of it) and then leave it on the IC for a few seconds. After that you can scrape it off with your fingernails (wash your hands after everything involving acetone of course).