> As for mashed avocado like guacamole, we think the best solution, aside from preparing it right before serving, is to press a double layer of plastic wrap dir

> As for mashed avocado like guacamole, we think the best solution, aside from preparing it right before serving, is to press a double layer of plastic wrap directly against the surface of the avocado mixture. Why a double layer? Does oxygen penetrate the single layer?