[Alan Brinton]

A bath will not harm metal reeds, Karen. Moisture collects on the reeds every time you play it. A water and vinegar solution (1/3 unflavored vinegar, 2/3 water) will alleviate the odor problem. Soak it for an hour or two and then rinse it well. Stand on end with the mouth side down. It helps to blow the solution out a few times, working the keys.

Because the melodica is metal and has metal screws, I would not leave it soaking for an extended period, for example overnight. Leaving it (dry) in a paper bag with baking soda will probably help it there’s still some odor, or you can repeat the bath process.