I’m working on a friend’s Meteor pinball. It’s really in good condition except it was stored for many years in a barn where the mice took it over for their residence. They dined on the wiring mostly, (seems they preferred green wire). I’ve replaced all the really bad wiring but there was still a bunch of places where they just took a bite or two. For those places I thought I’d try liquid electrical tape. It worked really good. I wouldn’t use it for large areas.
A few pieces of advice – it’s really messy so put a paper towel under your work area and don’t get it on you (you’ll ware it for a day or so).
Hope you find this tip handy.