Oh, Bee is so right! I started out with pine shavings that were way too deep and didn't get any kind of effective break down. But I listened to her (my friend and mentor) and cut way back, added a little water from time to time, and mixed stuff in that was bigger in composition - leaves WITH the small twigs still in them, weed clippings, a little straw now and then, etc - and I heaved a few shovels full of garden dirt over all to kick start it. The litter I have now is nothing like what I had before.