Quoted from cottonm4:This question was raised in another thread yesterday.
https://pinside.com/pinball/forum/topic/best-way-to-clean-entire-em-cabinet-mechanics
Spraying water on wood makes me nervous. I'm sure it will clean quite well, but getting wood wet doesn't sound right. You could gut the cabinet and spray-n-wipe with your favorite cleaner. Someone talked Purple Power; I like PP. I also like Zep Industrial Purple for cutting nicotine.
For cleaning the relays and switches, I would remove the relays board from the cab and get some automotive spray brake cleaner and spray it down. Brake cleaner is not water based so it will not hurt your electrics. It is flammable so you would need to let the parts dry for several hours before you apply power.
I was shocked the first time I saw an empty Pinball cabinet being sprayed out with the hose and nozzle. Tim Meighan, one of the Premier EM restorers in America, who lives in Seattle, showed me this technique at his house one time and I about fell over.
Since then, I’ve done it on numerous cabinets and as long as you dry them out in the sun and/or with fans, they are totally fine and it does not hurt the wood at all.