I was wonderibng if anyone knows of a method to get a rust treatment inside the hollow frame members. The insides of mine on my 67 Charger are pretty rusty as I have sprayed a water hose in there and lots of loose rust has fallen out. I therefore want to spray Por-15 inside it to do what I can to slow the deteriooration of what metal is left. I was thinking that maybe a bug sprayer bottle could be used but maybe I would have to thin the paint. I have a small pancake compressor but no paint gun as yet. do paint guns have nozzle extensions available? There are various factory holes in the square tubing that I can get a sprayer nozzle in to spray or squirt the paint. What do yall think. TIA for any responses.