Nice pics, dammage doesnt look too bad. Personally, i use q-tips and isopropyl alcohol to clean boards.
My board looks similar to yours in regards to dammage. The copper fill around the battery on mine looks clean like on yours, but i had battery leak in a 4cm radius around the battery. Most bad dammage was on the leads of the dip sockets. I had to remove a socket. I didnt bother to replace it though, soldered the chip right onto the board.
Clean it as best you can and dont worry about it. If it works fine, thats great. If it eventually starts acting up, clean some more. Id say that eventually it will fail at some point.
as for getting closeup pix, i use an iSight(fire wire chat cam) on a mac with a program called Boinx Ivzeen. This program lets me manual focus the camera, and the camera does really good close shots.
Here is an example of a pic i made the other day, using the isight and manual focus + screen grab. Its of some wires i soldered to an IR tranceiver module.
