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 or sachet form. A preferred composition comprises up to 60 % thiourea or a derivative thereof; up to 4 % surfactant; not more than 40 % acidifier; less than 20 % disintegrant; up to 10 % binder, 0 - 1 % lubricant and up to 40 % diluent.