Just give it some love. Add something to it. Others have suggested mixing it with new potting soil and that's a good idea. I'm one of those organic nuts and so I'll feed it with whatever I have handy. For example, maybe some liquid seaweed, or a little fish emulsion (yum), or liquid molasses, and throw in a few earthworm castings, maybe a few drops of orange oil, just all kinds of good stuff. Of course I was lucky in a way b/c a farm to market store a few miles away was closing and selling everything at 75% off. I really stocked up! But it's all good and I'll use it all eventually. I do tend to be a lazy plant abuser but it's nice to have the good stuff handy.
On the other hand, you could probably just re-use your potting soil without doing anything to it.
And on the other hand, please don't dump it. Waste not want not. (Did I really just say that?)
