Theres really a myriad of ways to clean stuff off. Can you stand the smell of some??? Oven cleaner is good for lighter stuff, but the fumes make me gag. A bucket of warm Fantastic with an aquarium air pump for a week is good. Being a good Catholic, have you considered cremation? A propane torch will burn the stuff down to ash and clean with a wire brush, but its smoky and stinks.
Soap based stuff only works for "oily" stuff. Real cleaning takes petroleum based solvents like the Kero and a wire brush deal, or if you have the means, steam cleaning or a 3000 psi pressure washer.
If my stuff is bad enough, Ill soak it for a few days with GUNK and hit the quarter (now $3.50!!!) car wash. Still is too oily to paint. NEEDS acetone or brake cleaner for dryness.
Of course theres always the little screwdriver for all the nooks and crannies like flat washer seats etc.too! ws
before the 10 cans of GUNK and $20 at the car wash
and after. went straight there even after the 600 mile roundtrip to get it while we still had the trailer