Not all stains come out in the machine. That statement may be contrary to what you’ve been told by product advertisements (i.e. Tide, OxiClean, etc.), equipment salesmen, or what you’ve convinced yourself to be true.
Stains fall into four distinct categories: solvent-soluble (dry cleaning), 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. The vast majority of water-soluble stains are either tannin (from a plant) or protein (from an animal). Water-soluble protein stains are substances such as blood, urine, vomit, bodily fluids, eggs, milk, yogurt, perspiration, and even
To some extent, all of these stains are affected by dry cleaning and/or dry-side pre-spotting. But to really remove protein stains, one has to go to the wet-side and use specialized (chemical) stain-removal tools.
The first decision you must make with a protein stain (like any stain) is to pick one of three starting points. You can go straight to the dry cleaning machine, perform pre-spotting or immerse the garment in water. Going straight to the dry cleaning machine only works on very small, usually fresh, stains. Most of the time, dry cleaning only postpones the stain removal necessary, and may even complicate the process.
Dry-side pre-spotting is much more effective on solvent-soluble, chemical-soluble and insoluble stains, so pre-spotting of water-soluble protein stains is only effective when you use a spotter that contains moisture. Even protein stains that may come out with a spray spotter are best treated with a steam gun and a protein-removing chemical tool. Water immersion is as old as or older than the industry itself, and a good digester bath is the still the most effective way to deal with old and/or large protein stains. Wetcleaning is the most recent strategy for the professional cleaner. Professional wetcleaning procedures are effective on a vast majority of wet-side stains, with limited effort required from the cleaner.