Originally Posted by Delta9
I will normally clean my airfilters about 4 times before throwing away, sometimes less if they look dodgey. as long as you clean it from the inside out its fine as it wont push the dust into airfilter, i use denatured alcohol or petrol to clean my airfilters.
I soak and gentle wash my filter with highly concentrated detergents, about three times cleaning process. After complete drying, I right away give filter oil and keep them in clean containers, ready for use anytime I want. Mostly they could last about a year.