This channel at the base of the door had a thick layer of black wet crud that I am almost done cleaning out using a plastic scraper, toothbrush & a lot of compressed air. I should've taken a picture of what it looked like before I started. Perfect place for rust to start:

 

That is a good place to clean that most people never think to look!

Thanks for posting!

 

i pull all the interior trim panels every fall in order to coat the inside of the body & doors with fluid film. also clean out all the drain passages in the pinch welds of the rockers.

 

Yes, I use fluid film all over: door panels, inside tailgate, up in the wheel wells, behind the rear lights, the voids in the hood, inside the fenders, inside the frame, spare wheel, etc.... Stuff smells great too!

 

fluid film works well, my only problem is the 5 to 7 vehicles i need to treat each year....

 

Good info in this thread! Fluid film eh? Just spray a nice.. film over things and it protects it, good thinking guys, will be adding this to my winter maintenance for sure.

 

This gun makes it a breeze to spray: https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
Gallon jug: https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

 

Here in So Cal, at least this^^^
I had a puddle of water in compartment behind the rear wheel-well. Fixed after I cleaned the drain there. Condensation must have built up in there.

 

additional note: i also spray the inside and outside of the chassis, along with most of the underside of the vehicle, front end suspension & steering components, etc.