COMPOSITION FOR CLEANING SILVER OR COPPER.

摘要

A chemical cleaning composition for silver?? or copper??containing surfaces consists of a water??soluble solid or powder comprising thiourea or a derivative thereof, and is formulated in unit application form, e.g. in tablet orsachet form. A preferred composition comprises up to 60 percent thiourea or a derivative thereof; up to 4 percent surfactant; not more than 40 percent acidifier; less than 20 percent disintegrant; up to 10 percent binder; 0 ?? 1 percent lubricant; and up to 40 percent diluent.