If you burn yourself with a chemical that reacts in an undesired manner to water, how is the wound irrigated to remove the chemical?

Say I burn myself in the forearm with a chemical, let's call it "chemical z," but chemical z reacts vigorously when submerged, how is the site of the burn cleaned to prevent further tissue damage? I say chemical z because I don't know chemical names, but I frequent the science side of YouTube.