How long to leave the vinegar on a faucet will depend on how severe your mineral deposits or limescale are. If your faucet head has stubborn limescale deposits, you can fill a plastic bag with white vinegar, then place it over the head and secure it with an elastic band. It can be left for 24 hours to ensure you remove all the deposits. Smaller parts, such as the aerator, can be placed in a bowl of vinegar for a couple of hours.