NiMh are a lot different than Li-Ion. Nothing wrong with at least trying on the NiMh. If you're charger doesn't recognize them because they might be near 0V, then outside the charger, place another battery in parallel with it to move some charge over to the depleted cell. Then it will pop right up high enough for the charger to recognize that something is in the cradle and start charging.
The last two replies talked about charged/partially charged, but old, batteries. Mine are depleted and have been that way for 2-3 years. Just clarifying that it should still be ok? Somehow I got it in my head staying depleted is bad.