So I got 2 out of the 3 gbcs I bought working . Ironically it was the 2 purple that worked out. I had to desolder the terminals on one of them the clean the battery corrosion on it. The clear purple game was very corroded, so much so that the A,B and Start buttons had no more traces left on them. The headphone jack was so corroded it was completely covering in blue. The negative battery terminal literally broke off with just a touch. The on/off switch was so corroded that the pads were completely eaten. From the pictures on the site, it didn't looks bad at all.
For some reason one of the gbc's won't work with reproduction cards, not matter how much I clean the cart slot. The other gbc had a bad speaker and the only decent speaker I had was from a ds lite. I had to cut the plastic a little to get it to fit, but it's working great.
Probably will be buying some more in 2 weeks to fix up