Nearly eleven years' accumulation of leaf debris in my fenders, visible in the openings revealed by an opened door. I posted before how I blew them out with a shop vac but it turns out I really didn't do much. This time I got ready big time; wheeled the old Craftsman compressor out to the truck and let it work up a head of air. Got my little 'Coast' 240-Lumen LED flashlight. Dragged the water hose over there too, but the best tool was the cheapest - an old wire clothes hanger that I stretched out and bent the hook into an 'L'. I proceeded to gently scratch out the debris from the lowest opening where it could fall out of the truck - it was tight and deep there. I continued with this higher up where the slim wire can get into a thin slot opening and above that in the larger opening into the upper fender above the wheel house. When I had all I could get with the wire I started blowing air into the holes which was pretty effective. Having the compressor also made for a fast clean-up where debris landed inside the cab. Next I used water spray from the hose at full pressure from a nozzle to blast stubborn debris off the seam in the upper fender area where the wheel house is attached to the fender, also noting at this time that the body drains were working. I tried to wash this down so I could scrape/blow it out of the lower opening. Finally I blew out as much water as I could and drenched everything I could get to in these spaces with water-displacing light lubricant. I used some stuff I got some time ago that I've been finding uses for called 'Super Slick Stuff'. No oil, no silicone or Teflon and it displaces water then dries. There are plenty of interesting 'oils' to use, not the least of which would be '3-in-1' 'Garage Door Lube' which is a strong silicone product that also waterproofs and has a very powerful spray straw to direct it deep inside any body spaces. What you want to use here is anything not oily or greasy, including WD-40 if that's the best thing you can get.
The hi-intensity flashlight is great for this as its small and plenty bright to help you see what you've done and what's left. Whatever product you spray in after cleaning should be paint and rubber safe. I used it all over the hinge areas as well as on the lower door edges after cleaning them with water and a brush where the door skin wraps.
After all this I treated myself to a little drying-out drive to Starbucks for a black coffee and a treat. If I do this every year it won't be as hard as it was today. The best news is I found no rust under any of it. Not bad for that length of time but I also never drive the truck anywhere road salt has been used until it has rained at least once.
I'll be working on the truck the rest of the fall weather. I have to do the annual oil change, drain/fill the power steering reservoir, D/F the manual trans (first time), wash the engine bay, wash the truck, treat the rubber/plastic and wax it.
Maybe I'll get another eleven years out of it.