Soil.
Here is how I cure my soil:

I put my vegetable kitchen discards in one bin, and I cover these organic materials with a layer of dirt from the other bin, then often spray on water (when the weather allows it or the spirit moves). I spread some manure on top every few dumpings. Other matter I add to the bin: ashes from my outdoor fireplace, and saw dust. I also add some modest amounts of grass clippings when available. When the bin is near empty, I start adding compost material to it, and I cover it with material from the other bin. It works well.