I had a leaked alkaline in my Fenix E01. The head was stuck, so I used vise grips to unscrew it, but the battery inside was also stuck. I sprayed Deoxit inside the light, let it sit there while it bubbled, and then smacked the flashlight upside down a few times. The battery came out, and it looks like my E01 is usable again!
Let this be a reminder to all those who trust alkalines with their toys (and tools), no one is safe, even a month-old battery can be provoked to leak.
Also, I was surprised how well Deoxit worked in this situation, though I won't guarantee it'll also work for anyone else.