Those wasps are annoying things.
I must of removed 10 of those mud nests from my machine's backbox when I first received it and I found another 2 the other day hidden under the wiring loom.
I have been lucky though mine were all on wood, so didn't cause any corrosion.
No so lucky with the coinbox door though that has lots of corrosion.

A sandblaster is the one thing I don't have in my workshop, but would really like to have one.

I'm just new to repairing pinballs so I won't comment whether to power coat or not.