Wonder if you have an oil film on those brackets. Wash them down with Brake Parts Cleaner to get any oil off, then maybe even light wire brush them to break the surface, then put them in new 5% or 6% cleaning vinegar overnight soak.
Next day rinse them down with distilled water and a scotch brite scuff pad. Then final polish them up on a fine wire wheel on your drill press. Should make them look like brand new steel.
After the vinegar dunk and distilled water rinse and blow dry, the parts are so raw that they will flash rust. That is when I polish them up with the fine wire wheel.
Engine parts I put a coat of WD-40 on them and polish them up with a scotch bright scuff pad, then blow them down and wipe them down with some paper towels.
Coated and protected till assembly.
Here is a picture of the crankshafts after vinegar dunk and distilled water rinse and blown dry. As you can see, they flash rust real quick in minutes, so get some WD-40 on them to stop the flash rusting.
Flash Rusted
Before:
View attachment 1715539983
After:
View attachment 1715539984
They Polish up nice, takes a little elbow grease.
