Tamar Adler said this quote

The bones and shells and peels of things are where a lot of their goodness resides. It's no more or less lamb for being meat or bone; it's no more or less pea for being pea or pod. Grappa is made from the spent skins and stems and seeds of wine grapes; marmalade from the peels of oranges. The wine behind grappa is great, but there are moments when only grappa will do; the fruit of the orange is delicious, but it cannot be satisfactorily spread.“The skins of onions, green tops from leeks, stems from herbs must all be swept directly into a pot instead of the garbage. Along with the bones from a chicken, raw or cooked, they are what it takes to make chicken stock, which you need never buy, once you decide to keep its ingredients instead of throwing them away. If you have bones from fish, it's fish stock. If there are bones from pork or lamb, you will have pork or lamb stock.