However, other metals with high reaction rates—such as manganese chloride 2 ... time of the patch-test readings. Given that we tested metal preparations of different salts and in different ...

Ferric chloride works as well ... making up etching solution from powdered ferric chloride. But the meat of the video below is the head-to-head test of three different masking methods.

Metals with extremely low rates of allergic patch-test reactions included zinc, ferric chloride, and tin. Reaction rates varied depending on metal salt, concentration, and timing of readings.