As Eddie said, potato peels are notorious for clogging drains. I remember ours becoming clogged on Thanksgiving when I was a little kid, after my mom made mashed potatoes, and ground up the peels. We were lucky, and the plumber could come on Friday. One time we went to visit friends of the family for Sunday lunch, and Marguerite served mashed potatoes. She put the peels down the disposer, and when we were finished eating, ran the disposer again. The drain was clogged, and dirty water went into the dishwasher. She opened it up to add a dish, and a tidal wave came out and ran across the floor. She sent her son Jack to the basement for a plunger and mop, but the plunger didn't do any good. Her husband Bill had to go to the basement, and open up the grease trap, and clean it out. This happened in March, 1962, and I remember it like it happened yesterday. I remember because one of their daughters had just got the record "Johnny Angel" by Shelley Fabares, and played it at least 10 times while we were there.