I've had very good success rate resurrecting cells around 2.5V, much lower and they often don't want to come back. It's worth a try.
mAH capacity can't be tested with a volt meter, you need a charger with test capability like the BT-C3400 or MH-9000.
As far as my "recycling routine", what I do is first is measure voltage and throw out anything under 2.5V. I then clean up the cells, often the laptop pulls my friends give me have glue or grout sort of paste on them from being in the laptop packs. I remove this, and any left over tape or labels. I clean them with paper towels and alcohol. The cells in laptop packs are usually welded together with metal strips, and when the cells are pulled away from the strips it leaves little metal weld burrs on the ends of the batteries. I get rid of these with fingernail sandpaper emery boards. A friend of mine told me a dremel would be faster, but I don't own one. After cleaning the cells, I'll charge, then discharge them 3 times, taking the mAH reading on the third charge cycle. If the capacity is under 2,000mAH, I figure the cell is pretty tired and I don't really want to mess with one that low a capacity anyway... those get discarded. After that, they're just like any other 18650 unprotected cell, I use them around the house in my extra Zebralights and Armytek Predators and Vikings, as all of those lights have under discharge protection that keeps the cells from going under 2.7V. I've occasionally used them in other lights without discharge protection, but I'm careful to not run them all the way down.
I hope this helps you!
