24/7 Washing a small sample of the black "money"

Since Then the conman will produce a small vial of the washing liquid and ask the victim to select any stained bank note at random. This done, the conman proceeds to wash the banknote in the chemical, performing a sleight of hand in which he substitutes either an already-clean note or one stained with dye that can be removed by the chemical. There will be insufficient liquid to wash any more money, or the conman may "accidentally" spill the remaining contents.