If they didn't cost you anything and they are dried out, you could try soaking them in milk. I have no idea about what the best ways to treat dried leather would be, but you wouldn't really be at a loss from trying (expect for the milk you use I suppose). I would be worried about the tips separating from the backing, but other than that, install one and see what happens.
I had a handful of old dried up tips as well, and I soaked and pressed half of them. If I ever have the time, I'll install them, test them out, and post if there were any differences.