You used to have to oil AEM filters. The older ones are similar to K&N. They just recently came out with their DRYFLOW air filters that do not need to be oiled
I know on the old AEM filter that I have, I would clean it and oil it about twice a year or more if I know it was dirty. how do clean those new ones? Cleaning and oiling the old style wastes a good 45 min.
The AEM DRYFLOW has a special cleaning solution that goes with it. You just clean it, let it dry and put it back on. AEM still sells the old cleaning solution and oil for the older filters that had to be oiled