[h13man]

Surface rust, clean with polishing compound and aluminum foil but will require constant attention. Depending on on condition, I'd have them sand blasted with a 120 grit aluminum oxide and use VHT High Heat Cast Iron paint per instructions. I highly recommend VHT products.

 

[h13man]

I might add that using glass bead will give a slight shiny finish which isn't a good finish for paint adhesion like aluminum oxide medium will give. Need that dull finish.