A question about chemistry and puzzle...?

A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull ornaments. An unsuspecting lady gave a set of gold bangles to him, which he dipped in a particular soluion. The bangles sprkled like new but their weight was reduced drastically. The lady was upset but after a futile argument, the man beat a haisty retreat. Can you play the dective role to find out the nature of the solution?