So I have some of the first rounds I reloaded where I didn't tumble them to get the lube off after resizing them. I just wiped the lube off of them before shooting them with a towel. Anyway, I've noticed now they appear to have spots of discoloration all over them. I'm not sure if it's rust or just discoloration. Is this stuff still safe to shoot and later re use? Or is it going to make the brass weak or something?