if it is 3" wide then a 12" piece should suffice--cut the outer skin off and spines and slice it into cucumber like slices, then dry it in the oven on low heat with the door open for a few hours--you just have to watch it--use a non stick cookie sheet or use the sun if it is hot and sunny and dry--not humid, or you could just root and grow the plant and get some peruvianus powder from us! Just a thought---have fun either way!