The Home Depots in our area have a new bag-o-stuff called EcoScraps and it is compost from veggies and fruits that go bad at the grocery stores. I would use that. If you use kitchen scraps before they have been composted be sure to bury and let nature take its course that way. Same with the coffee because you are amending IN the enclosure. Mix the grounds with soil first and then bury near the plant roots but also in a place where your tortoises may not burrow. Maybe add a brick or rock on top to be sure your tortoises do not dig in there for a few months while things break down.