som jeg viser til i ett svar noen plasser ovenfor mekkernmekkern skrev:bomullsfiltre har egne rensevesker og oljer.

forøvrig har jeg funnet denne linken om hva og hvordan BMC lager sine filtere. http://www.linkauto.com.au/history.php?id_company=11" onclick="window.open(this.href);return false;
Jeg er ikke så stødig i engelsk , men der står det bl.a.:
..filter must be very light, must be made of the best raw materials and must improve performance. For this reason we use only alloy mesh with epoxy coating to ensure protection from petrol fumes and from oxidization due to the humidity of the air. The filtering material is composed of a special cotton gauze soaked with low-viscosity oil to give you the best air permeability