There's an outlet above my stove inside a cabinet that provides
electricity for my microwave. Unfortunately, the circuit it is on is
overloaded with other items at times so I am in the process of running
a dedicated line from my circuit breaker box to the microwave outlet.

Ideally, I could just remove the overloaded circuit wires from outlet
and connect the wires from the new dedicated circuit to the outlet.
However, what do I do with the leftover hot wires from the old
overloaded circuit? I can get to the ends of the wire (obviously
because they were attached to the outlet) but I can't get to the rest
of the wire because it's inside the wall...

Note: the wires from the overloaded circuit outlet are at the end of
the run (no outlets after it so just terminating it is OK).

Thanks for any feedback...
Kevin