4 Cleaning reusable air filters is seldom done properly by the average consumer (including us). It’s necessary to use an extremely low pressure water source (in other words, have your hose barely turned on when washing). Too high of a water squirt, and the cotton inside the screen mesh of the filter can become slightly displaced. If this happens, it can allow some smaller particles of dirt inside, and that’s not good. The Synthamax air filters, due to their unique filtration media, can be a little more durable when washing. If you’re using an oiled air filter, make sure to gingerly oil the filtration media after washing. You can always add more oil to it later. The oil wicks through the filter very well, and we’ve been prone to sometimes over-oil our filters in haste. This can lead to oil leaking off the air filter and into the air intake tube.