Seattle Times: Though still largely dependent on a hazardous chemical, the dry-cleaning industry has worked hard to clean up its act. Of the more than 300 dry cleaners in King County, at least a third promote themselves as green in some way. But just as dry cleaning isn’t totally dry (it uses liquid solvents), “eco-friendly dry cleaning” is not always what it seems. Perchloroethylene, or perc, has been the solvent of choice for dry cleaners since the 1940s. It cleans clothes effectively and …