Nice game mate, should be a great bingo to play. I reckon they always got filthy, they were, at least over here, always in greasy spoon cafes, and everybody smoked.
When I first saw the Dutch guys video, I thought, no way. I watched it a few times and, every time, it stunned me the way they soaked literally everything, wood, electrics, motors, transformers, steppers, relays. I thought, that's got to cause damage of some kind. But I have a County Fair they restored 4 years ago and it works like a dream. I was going through a Sing Along with a dirty motor board, so I thought, lets try it. The result was: no damage and a lovely clean board. All the switches and relay ladders look near new. As I said, it didn't clean the wiring that well but I'm sure your game will smell like a flower garden if you use the right cleaner. I used an all purpose kitchen cleaner recommended by a fellow bingo nut.
I, and I'm sure others, would love to see a few pic's as you restore your game. All that tumbled metal will be a lovely sight. Post us some pic's, and let us know how the looms come up. You might hit on a brilliant method we could all use.