Onion skins
Apple cores
Garlic skins
Potato peels
Carrot peels
Pineapple peels
Bell pepper seeds
Zucchini tips
Corn cobs
Lettuce parts
Squash seeds and peels
Green bean ends
Beet parts
Celery leaves
Melon rinds
Spinach stems

Cabbage, eggplant, citrus rinds, banana peels, or too much celery can make your stock bitter.

Collect your scraps and refrigerate them in plastic bags or tightly closed containers until you have enough to fill half a kettle. Cover the scraps in kettle with water, bring to boil and simmer, covered, one hour or so. Cool it and strain it.

Any extra can be refrigerated or frozen for future use.