This Thread kinda caught me off guard, so I'll just post the little that's on the tip of my head at the moment...
I keep paper towels in the shop, for whatever one would use them for, but for most things BUT Flammables, I keep/scrounge/salvage old clothing for rags...I keep a cardboard box for their storage...all "re-used". I tear up/wear out a piece of clothing, keep it...they're good rags. They get a bit a "mess" on them, put them in a separate box and wash them, even HAND Wash them if need-be, and they're good again. I use some very cheap, Dollar Store Antibacterial Dish Soap to clean alot of things (like the cloth rags, ice chests) with.
To be continued...