How do I clean antique currency?
Asking for a friend: this 1929 Great Crash rarity has “foxxing” a type of mold in the “rag” (cotton) paper stock. Many people say, don’t touch it, others say, someone must know how to clean them because the dealers sell clean currency.Chlorine bleach is caustic and leaves a slick residue. Dawn has too much blue food coloring in it. TIA