99% Isopropyl Alcohol - for all of it. It is one of the best solvents around. The 70% Isopropyl will just frustrate you. Get at least 91% (very easy to find) and shoot for the 99%, if you can get it.
- windows (gets that greasy film off the inside of your car windshield - especially good with a microfiber cloth).
- any hard, shiny surface.
- weld prep. Degrease with isopropyl alcohol, then hit it with a clean stainless steel brush
Benefits:
- Dirt cheap.
- readily available at any local pharmacy (I get mine at the Safeway grocery store).
- environmentally friendly (breaks down into harmless stuff).
- no protective mask needed while using it.
- doesn't turn into dangerous fumes when welding (though it WILL catch fire...give it a few moments to evaporate)
- evaporates quickly, after you put it on.
99% isopropyl alcohol (dis)solves a lot of problems in the shop.
Your other option here is denatured alcohol (which is made from the same alcohol you drink, but 'denatured,' which means to put a chemical into which makes it poisonous to drink...so they don't have to collect the liquor tax on it.)
For strictly cleaning windows, a mix of ammonia and water is as good as isopropyl alcohol...and what the 'pro' window washers use. (just be careful to keep it away from anything with chlorine in it and be careful around the fumes).
Goo Gone for removing label residue.
But, generally, it is hard to beat simple old rubbing alcohol (isopropyl alcohol) for any degreasing or cleaning or dissolving around the shop.
Kev