Hahaha..my opinions are only based on years of experience (and a little bit of an MX background thrown in).
Head to the local motorcycle shop and buy a can of PJ1 foam filter cleaner and a bottle of Maxima FFT (Foam Filter Treatment). To wash the filter, spray it down really well with the PJ1 cleaner, and rinse it out with water. Repeat this until the water running out of the foam when you squeeze it is clear.
Then, drop the foam into a plastic bag (sandwich bags work well) and pour the blue Maxima oil into the bag. Work the oil into the filter while keeping your hands on the outside of the bag (the oil is very sticky). Once the foam is thoroughly saturated with the blue stuff, squeeze out the extra, and put it back on your car.
And for future reference..please title your threads to describe what you're asking about.
Aaron Waldron - LiveRC