P.S.

On ACL (Applied Color Label) bottles with rust I use the same submerged soaking process but use the soft side of the sponge for cleaning. If the ACL is weak to start with, I just leave it as is other than a slight cleaning with a moist paper towel. But if the ACL is strong, a light scrubbing with the soft side of a scrub sponge usually does the trick. Just be careful and don't overdo it.