If you have anyone in your area that does vapor blasting that would leave the best finish on your pulley drive surface. I recently purchased a vapor blast cabinet for my motorcycle shop and it is awesome.With the media suspended in water it blasts indirectly,the finish left behind is smooth and shiny VS the dry/dull finish of dry blast. Bare steel seems to be resistant to flash rust and it wont remove any stamped in numbers either. I bought it to do mostly aluminum parts and use glass bead mixed with the water.

https://vaporhoningtechnologies.com/