I just cut a small hole in the bottom of the aileron to get to the torque rod. About 1/2" from the hinge line. I usually make the hole square so I can cut a "plug" from balsa.

Then fill the hole with epoxy and fill with balsa.

If I am lazy and I don't care baout looks, I just fill the hole with epoxy and leave it.

This is much easier to get the epoxy in and less chance of the epoxy getting into the hinge area.