speedo face repair

[Piper]

ON the UC mark 2 we're working on the speedometer face is really badly rusted. I haven't done anything to it yet to see if there is something salvageable. My first thought is some CLR with gentle rubbing to see if we can get to what's beneath. I'd really like to clean this up as you can see some numbers on the face where the rust isn't too bad.

If it needs to be repainted etc, what's the best way to go?

Cameron