It is important to clean and oil your engine air filters on a regular basis, or at least during an annual condition inspection. Simply remove the The UNI UP4200 filters on each carburetor using a flat-blade screwdriver. After removing the metal band, spray the foam filter element with an approved cleaner such as the UNI Foam Filter Cleaner and Oil (https://unifilter.com/cleaning-oiling/). Wait three minutes, then wash the filter element thoroughly in running water. After the filter has dried completely, spray the filter element with foam filter oil (the oil traps minute dust particles) and secure the filters to the carburetor flanges. Easy Peasey.