when i run out of k and n red stuf i was told to use wd 40 by meknik- same kinda stuff. // I have those never replace just clean and oil air filters. What do you do with these things... First of all how do you clean them, and second, what type of oil do you soak them with and how much oil do you soak them with. Last, are these better than just buying air filters when it is time? Thanks.