Carbon or Corrosion

[SaboTron]

Is this carbon or corrosion on the valves?

Thanks

[1fst400]

looks like carbon build up that someone tried to polish off.

[SaboTron]

You are right. Just brought it to a shop and they said it was carbon. I was surprised because you can still see the lettering on the valve through the carbon.

[1fst400]

I would blast it off in a glass bead cabinet, then replace the valve seals and anything minor that may have been damaged