After every time you use your bit wipe it with a damp cloth or dunk it completely into a pail of water. When you’re done be sure to completely dry it with a cloth to prevent rusting. If you dunk your bit into water, remove it from the bridle first to prevent the leather from getting wet which will cause mold and mildew.
Every couple weeks you should clean your bit well with a cleaner. Be careful not to use any harsh chemical cleaners, remember that it’s going to be going into your horses mouth! The best cleaner to use is human toothpaste. It kills bacteria and is safe for the horse to ingest. It’ll even give the bit a minty taste which most horses enjoy.
You can use a toothbrush to remove dirt and grime from the bit. Be sure to clean the joint of the bit where the two metal pieces hook together.
Proper cleaning and care of your bits will make them last for many years without rusting.