Not all stains come out in the machine. That statement may be contrary to what you’ve been told by equipment salesmen, or what you’ve convinced yourself to be true.
Stains fall into four distinct categories: solvent-soluble (drycleaning), chemical-soluble (using additives), water-soluble (steam spotting, wetcleaning, laundry), and insoluble (lubrication and mechanical action). Stains that originate from a living thing are usually water-soluble.
