+1
a good way to dry out cacti is to cut the cactus 6 ways (long). if you have a sharp knife, cut out the white, and if possible, take off the waxy-skin like outer layer. when pealing it, it should come off clear. then take your dark green layer, and cut it extremely thin. once cut, lay the thin peices of green tissue on a glass baking pan. put the pan in a warm/dark place (i used a heating vent) and let it dry. the thicker the peices are the longer it will take to dry. (do not use the sun for heat... i find it makes the cacti less potent)