A bit similar to asking for coffee grounds, for use as a fertilizer.
i asked at a local cafe a few years ago and provided them with a nice new B&Q orange bucket, which they managed to fill for me in quite a short time.
I put this on the allotment, but after reading somewhere too much coffee isn't a great thing for the soil, i stopped. The bucket was later changed into a nice tomato pot, after a few holes were drilled.