No writing is wasted. Did you know that sourdough from San Francisco is leavened partly by a bacteria called Lactobacillus sanfrancisensis? It is native to the soil there, and does not do well elsewhere. But any kitchen can become an ecosystem. If you bake a lot, your kitchen will become a happy home to wild yeasts, and all your bread will taste better. Even a failed loaf is not wasted. Likewise, cheese makers wash the dairy floor with whey. Tomato gardeners compost with rotten tomatoes. No writing is wasted: the words you can't put in your book can wash the floor, live in the soil, lurk around in the air. They will make the next words better.