Re-hydro of steel Epoxi coated tank

[USNCVA34]

I have about 10 of the old steel 72's  If it is a US Divers/Aqua-Lung with blue colored interior coating, it is not worth the effort to clean it out. The blue stuff is all but impossible to tumble out in my experience. I built my own tank tumbler.

If the coating is brown, white or gray in color, it tumbles off with a little effort and time.

Something else to consider is the exterior. The early US Divers yellow tanks were not galvanized. I personally don't care to bother with those. If the tank looks smooth on the bottom, is not blue inside and the tank is galvanized either bare or painted, I would certainly tumble, hydro and use.