DRY CLEAN CHEMICALS used by the vast majority of cleaners - tetrachloroethylene, (perchloroethylene or "perc"). This solvent is the latest in a long line of chemicals used to clean stained but delicate textiles. Individuals working in dry cleaning became ill from using these chemicals. Dry cleaning is thought to have been discovered by accident in 1825 when a worker in a French dye factory knocked a turpentine-fueled lamp on to a dirty tablecloth and noticed that when the spill evaporated, the stain disappeared. Avoid this xenoestrogen.