I worked with sulphuric acid systems for 15 years as a professional engineer and I can tell you straight that it certainly does eat mild steel... There's a technical reason for why it doesn't attack it at very high concentrations (it creates a passive layer) but at up to 80/90 %, it murders mild steelODDITY.... sulphuric acid will dissolve almost anything (inc fingers) but will not attack mild steel, it does attack all other types, which is why commercially sulphuric acid is stored in mild steel tanks
I use cheap white vinegar in a pvc tube. Have used downpipe and larger soil pipe. works a treat.Soak it overnight in Citric acid.
The scale just wipes off the next day.
For bars and strips get a length of drainpipe with a plug in one end.
if you have space you could even use a length of guttering as a soak.