I have always clipped the end of the spines on all of my rays. Here is what I do.
Soak a towel in tank water. Lay the ray in the middle of the towel and fold the sides over to cover him completely, but leave his tail sticking out. Make sure the towel is WET, not damp. You don't want to remove any protective slime layer with the towel. Pull the sheath back that covers the spine. Take a pair of nail clipers and cut off the end so that it is flat and not pointy. Then get you ray back into the water. It's painless and takes only a few seconds.
If you pull the spine out, he will only grow a new, sharper one. But if you leave the spine in place and only clip the end, it won't grow back sharp again. If he ever swipes you with his tail, the blunt end of the stinger will not go into you. There tails are not just defensive weapons. They can and will use them in an aggresive manner if they don't feel well, or if they are having a bad hair, er bad fin, day.