Prickly Paint?

Rancheros from old Baja used to (and some probably still) make whitewash paint from prickly pear cactus slime, lime (not the kind from trees, but calcium hydroxide) and salt. I found a recipe on the web a couple of days ago, marched out to the garden with my pruning saw and hacked up some paddles to soak. The water is supposed to get slimy--slime equals glue, I think. Maybe it's slimy. When I dip my hand in, the liquid comes off in an even stream, not in drips like water. I don't have any lime yet, and need more salt. Of course, I would never be satisfied with white, but plan to use red iron oxide powder, yellow ochre, or pick up some red clay by the roadside. Stay tuned.