C5 air filter shock!

[white exec]

Interesting that our OE and similar replacement filters tend to be paper, and therefore limited life, even if blown through with an airline. Price ok if you shop around (eg PSA's Mister Auto).

Our Toyota RAV4 D4D is fitted with a cotton close-concertina'd filter, which can be blown clean, and also repeatedly washed. Toyota's service manuals list both these operations. I guess K&N filters are more or less similar.

The dirt that comes out when washing (in the sink, with warm water and a touch of bio fluid) is extraordinary. After a rinse, trapped water is removed with an airline.

[JohnD]

This is the engine that was in my first car. The cylinder mounted on the top of the engine is the air cleaner. It was similar to a silencer but the end was packed with very course wire wool. Periodically the end had to be washed out in a bowl of petrol and allowed to dry. Then the wire end was saturated in hypoid oil and allowed to drain before refitting.