I have a vintage wireless keyboard from 2011. I cannot get the cap off to change the batteries--Apple refuses to help me. Does anyone have any ideas how to get the screw off cap to loosen? I

Stand the keyboard on end with the battery compartment pointing up. Use something non-marring, like a wooden cooking spoon, and not too heavy to GENTLY tap at the points indicated below:

That will often loosen any debris or corrosion that is holding the cover closed.

If you get the cap out, clean it and the threads that it engages, then put a thin layer of petroleum jelly (Vaseline) on the threads of the caps to prevent it from seizing again.

If you haven’t used it in a long time, the metal elements oxidized and fused together.

Find a coin that fits the screw slot well and don’t be afraid to use some force on it.