Replacing an A2000 battery

I am currently in the process of replacing my Amiga 2000's battery... On the one I was finally able to remove there *seems* to be some damage to the circuit board that was underneath and nearing the 68000. Instead of the circuits being a nice green colour, it is now black. Is there any way to tell if this is only a colour change? Also, it looks like some of the copper has been eaten away around where the negative part of the battery was soldered to the motherboard. I have cleaned all of the white crap off with vinegar and a toothbrush. I then used "Precision Electronics Cleaner" from RS which is _supposed_ to leave no residue. Also, how are the solder tabs affixed to the battery? The replacement batteries I got don't have any. Cheers, Bryan Pope