Dry cleaning is any cleaning process for clothing and textiles using a chemical solvent other than water. The solvent used is typically tetrachloroethylene (perchloroethylene), abbreviated "perc" in the industry and "dry-cleaning fluid" by the public. It is often used instead of hand washing delicate fabrics, which can be laborious. The ancient Romans used ammonia (derived from urine) and fuller's earth to launder their woolen togas. Fullonicae were very prominent industrial facilities, with at least one in every town of any notability, and frequently the largest employer in a district. These laundries obtained urine from farm animals, or from special pots situated at public latrines. The industry was so profitable that fuller's guilds were an important political constituency, and the government taxed the collection of urine. Modern dry cleaning uses non-water-based solvents to remove soil and stains from clothes.
Contributions by Klonimus, Zsero, and Idrvball.