Compost.

We keep this compost cage at the top of the garden. All our organic household waste goes in here, including grass cuttings and garden/greenhouse waste. We should be able to use it next spring. Within a couple of days of filling it to the top it rots down again. I thinkthe hard job will be laying it on a tarp and mixing it as its layered with grass, organic household waste, eggshells, cardboard, garden waste, coffee grounds, shredded paper etc.
The are two free coffee machines at the Halliburton facility where I work and the guy saves the coffee grounds for me.
Coffee grounds are helpful in more ways than just compost. Slugs and snails dont go near them.