I use the K&N filter recharge kit. Spray it down good with the cleaner. Let it sit for a few min. Then take the garden hose to it. No nozzle on it, just a nice steady stream. Rinse good. Then shake the excess water out & let it dry overnight.
The next day I use there oil to lightly oil the tops of the ridges. Let it sit for an hour & oil any light spots there may be. Let it sit overnight & reinstall it the next day.
Mine usually last 40,000 miles or so between cleanings.
I got a drop in bedliner this year. Just got a chrome grill off a member here for 60.00 shipped. Just got it today so I haven't got it put on yet. I orderd some wheel skin chrome wheel covers. They should be here in a few days. Not going to do much more. Just trying to get away from the fleet truck look a little.