I bought the filter kit, but thats a tenner and includes spray oil. The cleaner is in a pump action bottle and only enough to clean a set of 4, twice.
As K&N's are made with cotton filters, its important to clean 'em carefully & also dry 'em slowly, so they don't shrink like your Levis's

I thought about some washing powder (DAZ) but not sure if this will be OK

It say's not to use solvent or petrol, as this will knacjer 'em
