Not really relevant now, but I get very large amounts of fruit stones and pips from all the fruit I grow and process. Many of theses seeds are viable, so if you put them straight on the compost heap, they have a tendency to grow when you don't want them to. But it seemed like such a waste to put them in the rubbish, that I bung them all in an old pyrex dish, and when the oven is on for something else I put them in to kill them off so I don't get forests growing all over my plot.