It depends on what kind you are using. Many are disposable/ for one-time use, though you can typically get away with using them a few times. If they are foam, which many of this variety are, you wont be able clean them with (hot) water, as it will cause them to expand, rendering them more or less inefficient. If you want a pair you can clean with hot water and reuse many times, try earplugs designed for swimmers. They are comfortable, quick to plug, usually come with a nifty case, and come in radical neon colors.