RealHomer,
I, personally use lemon juice then followed by IP and a distilled water rinse. I have done alot of A2000s this way. The biggest problem is it can go under the sockets of the CPU, ROM, and such, and can be hidden that way. If this is the case, you will have to unsolder the sockets and put new sockets in. If you can solder, this is easy, but if you can't, this can really hinder the progress.
If you can solder, I would also suggest replacing the caps at this time also, as you already have the motherboard stipped out anyways.
If you can't solder, then finding another A2000 (if you are in North America) may be an easy and cheaper alternative, and transfer everything over to the new machine. Nice thing is you don't have to re-install from scratch, just plug and play as you old hard drive is already set up.