what kind of media to refreshen spare gears with

Hello Apex,



My car came with tons of spare gears but they have been sitting since 2003 and have gotten surface rust on them. The surface rust is only on the teeth area. I have a dry tumbler and was going to put them in there to clean them up but what kind of media should I use? ISF?



Thanks,

Jon Updegrove

me_jeu@hotmail.com

610-509-7321