Read the above stuff, and combined ideas. Got it to go with:
* Vinegar applied with a Q-tip
* Heat applied with a lighter
* A quarter in a vice grip (with the smallest amount possible proud of the grip to reduce bending), tapped into the slot with a rubber mallet, while keyboard is on opposite edge on a wood surface.
* Twisting force with quarter in slot while holding keyboard, both tighter and looser, back and forth. This process three times, then it unfroze.