Game Boy game cartridge file deleted itself, battery is a 2016 from 2013 and measures 3 volts

[Gameguy]

While I agree with what youre saying, can we stop calling the corroded pins/boards "dirty?"

They're not usually corroded, they're oxidized. I have come across games with actual corrosion on the contacts but just a few times, and I cleaned them off but needed to open the cases to do so effectively. They can corrode with certain contaminants left on the contacts, including dust and dirt which trap moisture against the surface.

Maybe I am being a grammar Nazi here but I think it gives laypersons the idea that they're "cleaning" the contacts, as if they are covered in dust, dirt, grime, when in all my years I have never seen a cartridge that was literally dirty, other than a copy of Thunder and Lightning where it was covered in this nasty grime.

They are still cleaning the contacts, just like with cleaning cassette playback heads, or cleaning VCR heads, or cleaning any type of electrical contacts. You would be cleaning away contaminants from the surface. Have you noticed that there are various products created specifically for this purpose and they're labeled "contact cleaner"? What would you call this process instead?

I have seen plenty of cartridges full of dust, especially with loose games that weren't stored properly. I clean off dirt and oxidation at the same time. More common than with cartridges, I see consoles with plenty of dust or pet hair in the cart slot including inside the connector.

I'm not sure the exact composition of the contacts. I always thought it was either gold or brass? Whatever it is, when it is exposed to the air, it tarnishes.

Being exposed to air, meaning it oxidized, not corroded. Most of the contacts from Nintendo games would be gold plated copper(thin plating which can get worn through), different consoles could be varied by using different materials. The problem is more with the contacts in the actual consoles as they're not gold plated, these are just cheaply plated, and this plated surface wears and transfers onto the contacts of the cartridges, and this is what oxidizes on cartridge contacts. I've seen these connectors with the plating completely worn away, and the metal underneath free to wear against the cartridge contacts, and this is again what transfers over and oxidizes.

That's why carts eork better if theyve been sitting inside dust sleeves for 30 years, unplayed. Don't know the science behind it besides just knowing the basics about how copper turns blue (Statue of Liberty for example)

Carts work better when stored in dust sleeves as they're more free of dust, and generally when stored this way it also means they were taken care of better and less played with in general. The more a cartridge is played, the more the contacts are moved against the console's contacts, meaning the more particles are transferred to the cartridge and become oxidized.