vintage industrial shelf brackets, nickel steel supports for glass shelving apothecary dental cabinet

Vintage heavy duty steel shelf brackets - these are nickel plated, probably made to hold glass shelving in a dental cabinet or something similar. 1930s - 50s? There's twenty-three brackets in the lot.

These need cleaning, and have a little rust spotting to the nickel finish. A little very fine steel wool would work wonders here, I think. But I'll leave that for you.