1. BRUSH IT
Toss or brush the avocado with lemon juice, vinegar or olive oil as a short-term solution.
2. DON'T DITCH THE PIP
Some swear that keeping the pip in mashed avocado, like in a guacamole, delays the browning process. I find it is only effective for the avocado that touches the pip.
3. BLANCH IT
It may sound tedious but many believe by dropping an avocado into boiling water for 20 seconds and no longer, then plunging it into ice cold water will stop it browning . It sort of works, but you must ensure it is not longer than 20 seconds as it can make the flesh bitter.
4. MASH IT
The best way of preserving a glut of avocado is to mash it adding lemon juice. Spoon into a glass jar ensuring it is no more than ¾ full because it will expand on freezing. Seal and freeze.