The best way to get the battery out is to desolder. But you can cut the metal tabs with wire cutters also. That's what I did with mine.
There are remedies floating around involving scrubbing the affected areas with alcohol or vinegar. iirc, it's actually a base (not and acid) that's corroding the motherboard. I haven't tried them though. Neither of my 2000s were leaking. I just ordered a 600 off of ebay with the clock and memory card. So I may be in the same boat here shortly.
If certain parts are toast, depending on what they are, you may be able to replace damaged components. Otherwise, you can get a new 1200 motherboard from a number of places for not too much.
brian
