They are simply K&N filters us motorcycle guys have cleaned and oiled for decades now. The example above is good for cleaning, but that is a non-oiled filter. Just get the kit from K&N and follow the instructions; it’s easy.
www.knfilters.com
How to Clean K&N Air Filter Products - Instructions | K&N
K&N air filter cleaning supplies are available for K&N cotton, synthetic and heavy duty synthetic air filters. K&N OE replacement air filters have cotton media and are cleaned with K&N Power Kleen Industrial Strength Degreaser and then oiled with a specialized blend of filter oil.
