I know this is a really old thread but if anyone suffers a leaked Alkaline battery the only thing I have found to really remove the corrosion is CLR. that stuff just eats up battery corrosion. I had a 1AA Dorcy light with an aluminum body that I liked have a AA get stuck in a similar manner. I just filled it up with CLR, let it bubble, dumped and repeated the process a few times. It ate up most of the corrosion and I was able to tap the battery out.
I also got a Used Wii game console that had leaked batteries in the remotes. CLR on Q-tips quickly cleaned them up. I have never had CLR damage electronics that were submerged in the stuff but use at your own risk. You could always rinse with distilled water to be sure to get the CLR out with out damaging additional things.