Many fruits — including avocados, bananas, pears, peaches, and tomatoes — will ripen better when placed in a paper bag. To hasten the ripening process of any fruit, place an already ripe apple or banana peel in the same bag and store it at room temperature. To ripen green bananas, wrap them in a damp dishtowel before placing them in the bag. Once your fruits have adequately ripened, you can halt the process by putting them in the refrigerator.
Some of the fruit from that bushel of peaches you just bought at the local farm stand are hard as rocks. Place the fruit with a few already ripe pieces or some ripe bananas in a plastic bag. The ripe fruit will help soften the others through the release of their natural gas. But don’t leave them for more than a day or two or you’ll have purple, moldy peaches.