That’s a good question. The most important thing we can tell you here is to not use harsh chemicals. Instead, use mild soap and water and make sure to keep your helmet in a cool and dry place. If there is any padding do not remove it or throw it in the wash. Wipe it down and leave it at that. If you have odor issues, there are sprays you can use and if you wipe it after each of your rides you should be able to prevent odors from forming.