Squeezing grapefruit, tangelos and oranges for fresh juice? Shred their skins to make a thrifty batch of marmalade on the side.
• Pick tamarillos, cherry guavas and ripe rose hips. All are rich in vitamin C.
• When digging yams, sift all the tiny tubers out of the soil. These root veges are related to oxalis and can be similarly invasive.