Post-cleaning spot removal is another part of the quality control process. Post-spotting, as it is called, uses professional equipment and chemical preparations using steam, water, air, and vacuum. Post-spotting involves a fairly simple process for removing a stain. If the stain had water in it to begin with (bean soup, for example), then it takes water or wet-side chemicals to remove the stain. If the stain was on the dry side (grease, oil-base paint, tar, nail polish), it takes solvents or dry-side chemicals to remove the stain.
In home laundry, most wet-type stains come out during the washing process. Grease does not. The opposite is true in dry cleaning -- it will leave the wet-side stains intact after the cleaning cycle. On the other hand, the solvent removes grease and oils during the cleaning cycle. The exception to this rule involves incorporating a "charge" of specially formulated dry-cleaning soap (an anhydrous emulsifier) into the cleaning cycle.
The dry cleaner will examine your clothes after cleaning is complete to see if any stains remain. If they do, post-spotting tries to get them out. A conscientious cleaner will remove the overwhelming majority of soil and stains, but there is always a small percent of very stubborn stains that may not be entirely removed for a variety of reasons, such as:
- Tannin stains set by heat and time
- Original dye stripped or faded
- Bleached-out spots or sun-faded materials
- Foreign dye deposit