Apple has had the small footprint Bluetooth keyboard for some time. The battery chamber has a very tight fit. I have one of the original models that takes three AA batteries.
I have had batteries leak and make it almost impossible to get them out.
My daughter had a newer 2 battery keyboard, and upon realizing the batteries were dead, could not get the screw cap off to change the batteries.
On Christmas Day we were fooling with it and her husband and I became obsessed with getting that cap out. We bent several coins, holding them with a vice grips.
Finally we got out a Dremmel and ground at that sucker until we got the batteries out. We tried torch heat to free it frying the Escape key. Once we did all this hacking, we got the old leaking batteries out, popped in some new ones. Amazingly, the darn thing still works. All except the Escape key.