Store unused avocado by smearing the flesh with lemon or lime juice or olive oil, then wrap tightly in plastic wrap and refrigerate. The exposed flesh turns brown due to a chemical reaction to the oxygen in the air; a process known as "oxidization" (as do other fruits like bananas and apples), therefore by creating a barrier between the flesh and air can prevent this discoloration.
Putting the avocado seed into a bowl of freshly made guacamole to prevent the dish from turning brown is a myth. The seed has no magic powers. The browning occurs due to the exposure of avocado flesh to the oxygen in the air.
Have an over-ripe avocado? Don't despair, use it on your hair! The use of avocados as a beauty regimen
dates back to the Aztecs where women used avocado slices under their eyes to reduce puffiness and even rubbed it straight onto their faces to protect their skin from the heat. The oils found in avocados are also great for hair because they act as a humectant which traps moisture.