Most fruits should be allowed to ripen on their own until they are ready to eat. Sometimes, you may open a fruit because you think it is ripe, only to discover that it could use some more time. If you have already cut your unripe mango, you want to speed up the ripening process as quickly as possible so that it ripens before it rots and you can enjoy eating it.
Cover mango with its skin as best as you can. If you only cut a small section of the mango, place it back where it belongs and cover the sections of fruit that are showing.
Place mango in a paper bag.
Place ripe bananas inside the bag with the mango. Bananas emit a natural gas called ethylene, which speeds the ripening process of fruits and vegetables. When placed in a contained environment such as a paper bag, the ethylene will remain trapped and will have stronger effects on the mango.
Cut up an apple and place this inside the bag as well. Apples also emit ethylene and are particularly strong when they are cut up. Make sure to remove the apple before it begins to rot, after about a day or two.
Place the bag on a counter in a room temperature area, away from bright sunlight or cold air, and fold over the opening so it is closed. Ethylene is produced in much less quantities when it is not at optimal temperatures, so keep it in a mild climate. Additionally, hot sunlight could cause the mango to rot.