Instrument panel circuit board coating or oxidation?

[Cayuga Kid]

So I have my instrument panel out from my 63 New Yorker and was going to clean the circuit board but looking at it I am not sure if it has a greenish coating or is it oxidation. The board itself is brown and I can remove the green off ok with rubbing alcohol but cleaning the copper is not so easy.

Don't want to mess it up by doing the wrong thing!

Thanks

 

[Polara_500]

The green is a protective coating from the factory.

 

[Cayuga Kid]

Thanks, it looked to perfect to be oxidation and that is why I stopped.