Just did it this weekend. follow the directions on the recharge kit, and dont use any other oil on it than what comes in the kit or you will ruin the filter. Wash it, let it dry, then oil it well, let it sit 20 minutes and look for any whites spots, then if you dont see any put it back in service, if you see any, spray some more oil on it.
POINT, you cna never over oil the filter, in fact for off road apps, they recommend spraying extra oil on it. The oil is what does the filtering, the cotton gauze is just there to hold the oil.