| abstract |
(57) [Problem] To provide a discoloring film removing agent and a removing method for a silver product. SOLUTION: This discoloring film remover has, as an active ingredient, the following general formula (A) HS-R-COOH (A) [where R represents a C 1 -C 2 alkylene group; May be substituted with one methyl group, carboxyl group or amino group, and the position is not limited. The amino group may further have its hydrogen replaced by an acetyl group. And / or an alkali metal salt, an ammonium salt or an amine salt thereof, or an aqueous solution thereof. As an auxiliary component, compounds that generate various ions and / or sulfonic acids can be contained. |