people have sand blasted and bead blasted brake rotors and clutch discs before. Sand blasting is too aggresive if you ask me,you damage them if you dont pass the nozzle over evenly and quikly.
Just glue a piece of emery sheet (not too low of a grit) to a hard flat surface and run the steels over them by hand in figure 8 patterns.
Done. De-glazed,cost 50 cents,dont have to leave the house.
RSD.