K&N Engineering 99-0621 Air Filter Clearner and Degreaser 32oz. Squirt

The K%26N air filter cleaner and degreaser arrived quickly, and I really like this larger volume option as well as the trigger sprayer instead of the "push down" type sprayer on the smaller bottle. It's easy to apply with the trigger sprayer and it allows most grit/grime to be rinsed off without much difficulty after about 20-30mins of soaking. Just be sure that the air filter is really dry (after rinsing/cleaning out) before applying oil. I usually spray this cleaner in the later afternoon, let it soak for ~30mins, rinse well to clean, and let sit in the sun for a little while. Then let it dry overnight inside the house (conditioned inside air is usually dryer than outside/in garage) and spray on the oil in the morning before heading out. Also, I suggest keeping a standard air filter around (maybe the one that was in it before you bought the K%26N or just a new, cheap paper pleated one) as a "just in case" you need to drive somewhere while your clean air filter is still drying.