The best method for cleaning an Outerwears Pre-Filter is to shake off any excess dirt and wash by soaking for 10 minutes with the concentrated Outerwears Pre-Filter Cleaner solution (1:15 ratio). After soaking, agitate the Pre-Filter in the Outerwears cleaner solution and water to remove any remaining debris and grime. Once the desired cleanliness has been obtained, shake off any excess water and air dry. If caught on a road trip or during a race without access to Outerwears Pre-Filter Cleaner and water, you can also remove a significant amount of dirt by simply shaking the Pre-Filter and allowing the excess dirt to fall off.