How to Clean Night Guard? Cleaning your night guard regularly is essential to maintain its durability and hygiene. Start by rinsing it with lukewarm water after each use to remove saliva and debris. Gently brush it with a soft toothbrush and mild, non-abrasive soap or toothpaste—avoid hot water, which can warp the material. Once a week, soak your night guard in a denture or retainer cleaning solution for a deeper clean.