I just cleaned mine -I took out everything that wasn't bolted down-and used a garden hose attachment sprayer-I sprayed everything down with Clorox outdoor house wash/bleach-then rinsed that out and it dry a good bit-then sprayed some heavy duty degreaser decarbonizer-and scrubbed that into the floor and then rinsed and squeeged that out,next day I went to walmart and bought a few quarts of indoor outdoor battleship gray porch and patio/floor paint-wasn't too expensive,and looks great,you can also try an epoxy paint-but the price goes up quick for expoxy,unless found on sale
use a heavy duty degreaser and a hard bristle brush to scrub. home depot sells a brutally strong concentrate in 5 gallon jugs, its ZEP brand and it looks just like purple power but about 5 times stronger. a pressure washer is also pretty handy. if youre going to paint it afterwards use cement etcher after its clean.
Get the stuff made by Zep. Its in powder form. Wet floor...sprinkle powder on floor. Let stand...then scrub floor with a stiff brush broom. Rinse off then let dry or squeegee. Then stand there and stare at your brand new floor! Yes it works that good!
Muriatic acid vapors will make any steel surface rust like you never thought possible....SERIOUSLY. Any thing within 20 feet of were you are doing work shit will get wicked fucked up. Be careful...PPE is a must.