To enable safe and sure selective removal of copper and to improve stability by incorporating thiourea or its deriv. as an essential component.

The copper remover is a soln. contg. thiourea or its deriv. which properly regulates the dissolution rate of copper from the surface of a body to be treated on which a copper layer formed by striking and a layer of silver or its alloy different from copper in ionization tendency exist, enables selective removal of copper without damaging the other metallic plating layer and acts as a leveling agent. The soln. does not contain cyanogen and surely reduces harmful effects on the environment and the human body. The thiourea or its deriv. is used within the range of 0.5-100 g/l. When the soln. is adjusted to ≤pH 2.0 by adding one or more selected from among sulfuric acid, hydrochloric acid, phosphoric acid and carboxylic acids, the effect of the soln. is further enhanced. The remover is especially useful for removing a copper layer formed by striking on a lead frame.