I have used PJ1 air filter cleaner and oil on all of my foam filters I have owned. It is a great product, that works very well. The cleaner takes all of the gunk off will ease. Then the oil protects your engine by catching the duct and dirt. Works great and recommend to all.
Easy to use. Good price. Have been using for over 10 years. Make sure you press out the extra oil from the filter. Also a pro told me no matter what cleaner you use you should clean with soapy water after you use cleaners in a small bucket you will see a little sand in the bottom of the bucket every time.