What chemical to use for cleaning oiled air filters

[Yaristeve]

I usually use the K&N clearner kit. But when I run out of cleaner (but still have plenty of the oil), I use laundry detergent. I figure it's cotton so why not use soap intended for cotton? Plus, detergent will get grease (or, K&N oil in this case) out. And finally, if you do your own laundry, you will always have some around! Use Woolite if you're worried about it being too harsh...