In Jay Kordich"s book Power of Juicing,he says lemons and limes are ok with the peeling.Oranges,tangerines and grapefruit have an indigestable airomatic oil.Commonly called zest that causes issues in the colo-rectal area.It is also used as comercial cleaners.He does recomend using the white rind and membranes for the bioflavonoids.I found peeling the organges to be to time consuming for me.But the juice was very good!!Good luck and happy juiceing!!