The biggest concern you'll have with acetone is its flammability. As long as you're accounting for that (good ventilation), you should be fine.Wow! Scary stuff there, I'll think twice next time I grab any old solvent off the shelf before welding something. I have used Acetone to clean for years because it dries so fast I always figured I was good to go, I'll have to check into that to see how safe that is..
It's specifically the perchloroethylene in the presence of an arc weld that is the concern. Stuff doesn't burn, but converts into the gas used to kill more people than any other chemical weapon in WW1