Oven cleaner in the blue can. It's chemically not much different from HVAC coil cleaner, in case you have access to that. Let it sit for 15 mins or so, then brush and wipe off with blue shop towels or terry cloth. I'm not averse to pressure cleaning, so long as you can dry everything after. Then there's stripping the paint; we've lost access to methylene chloride, leaving a bunch of weaksauce on the market. I'm thinking the N-Methyl-2-pyrrolidone strippers are what I'll be using on my next project.