Unripe avocadoes can be kept at room temperature outside till they reach the preferred ripeness for eating. If your avocado has reached optimum ripeness and you are unable to eat them, you can keep a whole, ripe avocado in the fridge. It will keep for 2 – 3 days till you are ready to use it. Once you have cut an avocado, sprinkle it with lemon juice or vinegar to stop it browning. Cover with cling wrap removing any air, and store in the fridge.