General Homemade Chassis cleaning tools
Mainly for rattling out muck when dry, or between drying out (hot-air gun on low) sessions (scrape out, dry out, scrape, dry....). Also, final internal prep before anti-rust, paint or wax treatment of long internal sections (e.g. rear chassis accessed from rear bumper region) Sills if you can get into them from the ends.
Then your trusty HD vac-cleaner, with some step-down rubber hoses taped onto wedge-tool can often get access, to suck a lot of (dry) matter out... can be a long winded job though :), 5 minutes it is not!