Prickly pear cactus fruit is the best variety of cactus to use when making juice.The fruit ranges in color from green to purplish-red, with yellow to red flesh. Because this fruit can vary widely in size, determining how much juice you'll get from it can be difficult. Cactus juice is simple to make; the only tough part is dealing with the prickly pear stickers, which can be rough on your fingers.
Place the prickly pears in a large saucepan. Cover them with boiling water, and let them sit 2-3 minutes to soften their stickers.
Pour out the water. Peel the prickly pears, and cut them into chunks.
Place the prickly pear chunks in a medium-size saucepan. Add enough water to cover them.
Boil 5 minutes on high heat, and then remove from heat.
Pour the boiled water and prickly pears through cheesecloth into a large bowl or heat-tolerant pitcher. Throw away the seeds, draining as much of the juice as possible.
Stir in sugar and lime or lemon juice, and then allow the juice to cool. Store the cactus juice in the refrigerator in a sealed container.