Here's a nice video on how to keep your engine bay nice and clean.
Very satisfying to watch.

https://www.youtube.com/watch?v=5R3GeFu56n4

I've owned the Firebird long enough now that I cringe whenever I see water entering the engine bay of any car.

lol. well you got a garage now so all the more time to dedicate to cleaning it up. haha

I did it by hand awhile back with some degreaser and rags and paper towels, will probably go over it again after I get around to doing the paint out.

seen it

I skimmed and didn't look at his product choices, but most wet dressings actually attract dirt and create grime even if they look good for a brief period of time. Dry dressings are where it's at, aerosol dry to the touch stuff on plastics and polishes and waxes on polished aluminum parts. When he scrubbed the bar with mag polish and steel wool he stripped any protective oxide layer from the bar, it'll re-corrode quickly and likely even uglier than before unless he does a proper polish and clear coat or religiously keeps it waxed.

Otherwise what I saw looked ok, I'd have masked off the fenders and hood to avoid over spray, some cleaners can be very harsh alkaline and damage gloss on fresh or single stage paints.