Gojo? That's a new one.

Remember evapo-rust is awesome, but parts will re-rust unless the exposed area is protected in some way. I smooth out pitting, make shiny, and do a light coat of clear.

If you're not restoring the playfield there's little point in magic eraser. I wouldn't abrade it with Novus products either. And avoid water-based products since they are, well, water. Wax seals in dirt but at least gives some protection.

It goes a long way too. You don't want gobs of it caked up all over, just even coats.

The pop bumper board is a simple circuit and easy to work on. If you're comfortable soldering, I'd just keep the originals. If not then it's a great way to learn, and I'd still keep the originals.

I buy the originals (broken or not) off eBay when I see them cheap. You can pick them up for like 4 for $8. I have a dozen or so extras. You can use them in System80, but they're also useful if you want to mod an older game (ie, System1) to have snappier pops. The board operates independently of the MPU, so it's a neat little part.

It's fuses. If you need thoses fuse sizes they're fine. If you work on many machines it's more cost effective to by larger packs of common sizes or "fuse breakers", but sounds like that's not you. Yet!

You seem like me where you fuss over getting "the right things". Just focus on getting your addiction firmly cemented and upgrade things later.

Yeah, battery leaked. You can see in the third-last picture where the alkaline has seeped over towards the reset section. See the dull green legs on the resistors? Still minor, so that's good.

Needs to be cleaned up, BUT do your homework first. It's easy to spread the alkaline while attempting to clean it.

That board damage is so minor, it would be a real shame to put it away as-is and let the damage spread. If you don't plan on cleaning it, you might want to sell it so it can be repaired and do someone some good.

My MPU board was corroded much worse than that and has been rock solid for over two years now.

Do not agree that the traces are fragile. They're wide enough you can walk your dog on them. Connectors and bad grounding are much more problematic. Best thing I did was repin all my connectors.

Anyways, the problem you have selling them is they are pretty nice but still "as-is, untested". If you can tell a buyer they work 100% then you can get a lot more for them. Look at sold items on eBay and here for price ideas. I pickup "as-is" power supplies for $10 or so, driver boards for $20, MPUs are more variable. Clean with no hacks like yours should get $25+. I'd bid on these guys if I saw em.