K&N 33-2023 fits '87-96 gas F-series/Broncos.
IF THE IMAGE IS TOO SMALL, click it.
I probably cleaned this in 2002, but I really don't remember. Since then, I put several thousand miles on it, parked it for ~4 years, then got it running again & put a few more thousand on it. There are at least 2 trips to Coon Creek & 1 trip to Hot Springs ORV Parks in there, interspersed with several hundred miles of WOT to & from each time.
I was pretty surprised to see how clean the clean side has remained. I really expected to see a layer of dust in the top of the box, but there's nothing.
Even after knocking a pound or so off onto the tire, it still took 1/2 a bottle of cleaning solution to wet it down, and the sink turned black on the first rinse.
I plan to take better care of it from now on. (Yeah, RIGHT!)