On a Chicago Coin SOUND STAGE I recently bought, all the plungers in the
stepper units were rusted and thus none of the stepper units (three of them
with about seven plungers in all) would function.
The solution I found that worked for me was to remove each plunger. Next,
using a circular wire brush mounted on a drill (about US$3 from my hardware
store) and holding the plunger with strong pliers, the rust came off. Apply
pressure as needed. To smooth, I then used 1200 grit sandpaper to lightly
sand each plunger. The 1200 grit also was great to lightly sand the metal
coil sleeves the plungers fitted into.
SAFETY FIRST! ALWAYS WEAR EYE PROTECTION AND GLOVES. THE PLUNGER CAN
EASILY FLY OUT OF THE PLIERS IF YOUR GRIP ISN'T STRONG ENOUGH AND DAMAGE
YOUR EYES. THE WIRE BRUSH WILL GRAZE YOU BADLY SHOULD YOU MAKE CONTACT WITH