Hello to all! I've been reading here for a long time but this is my first post 😀
Recently I bought this motherboard with a 486DX-2 66MHz on it.
It had a corrosion problem that I thought I could fix. Now, I am not so sure tbh.

You can see in images, I have noted the problematic area (image: Corrosion_Explained)
1: This is the yellow pin on P8P9 connector. Because of the corrosion, it is now short-circuited to ground (area 2, 4pins)
2: These are the black pins of P8P9, ground.
3. This is the damage. I think, the battery corrosion ripped off all the copper mask (this is the term, correct me if I am wrong). So now, the lanes that should be in green are actually exposed and you can see the copper.

I removed 4 capacitors and the P8P9 connector.
I used a multimeter to check continuity and the results:
- Yellow pin of P8P9 is connected to ground (it shouldn't)
- Capacitor wholes in area 3 are all in continuity.

I think that I have to somehow isolate (mask?) the exposed copper so the continuity stops?
I read about nail polish but I am not sure if this is a valid solution.
Any ideas? Is my approach correct or need to do/check something else?

Thank you all in advance!
Giannis