I have attached pics of my CPU cooler it got stains and they are permanent, a week ago i removed thermal paste with 70% isopropyl alcohol and now when i checked again it got stains which can't be removed. I tried again with 70% isopropyl alcohol swab but they are not removing and seems like they are permanent now. Are they harmful? Can i reuse my cooler again or can these stain get removed with any way?