NEVER!!!! You paid big bucks for the worlds best filter, why the heck be a cheapskate and use something other than the recommended product to clean it? when I was young and stupid back in the early 70s when I first started using K&N I cleaned a couple filters with solvent, like I said I was young and STUPID.
well if anyones noticed or not, if u smell castrol "superclean" and the K&N filter cleaner, they are identical in everyway, i've used superclean and it works just as well, and u can by it in differnt size bottles and dilute it. .hope this helps!
I think the off-road industry will see some changes in what is the preferred filter for off-road vehicles especially, but all vehicles eventually.
Dirt Bikes riders have always been into air flow improvements (a lot of nice stainless steel exhausts out there) and keeping dirt out of their bikes' internals. The foam filters are superior in air flow and trapping particles of dirt. In fact, when dirt bike riders use a K&N they usually have a foam 'sock' that goes over it.
I've had K&N filters on my cars for years. I have a friend who started a filter oil company called No-Toil. He showed me the emperical results of foam v. fiber v. paper and it's pretty obvious. He sells all sorts of filters and had one tha fit my MPI intake for under $30.
The No-Toil trick is in the oil. It is environmental friendly and can be washed safely in the sink, washing machine, since it doesn't need solvents to clean it. It is not a petroleum-based oil.
I used it on the Rubicon and was amazed at how much more dirt was trapped than the K&N I have been using. So, when I want to clean it out I can wash it in the sink with their biodegradable cleaner, then apply new oil. It's too simple and it makes sense.