Neighbor and customer called with blocked Lav. Pulled trap , but top gun wanted up vent only. So Bigger machine up on flat roof to 1 1/4 " vent. ran water hose N cutter out and back a few times ,could feel it break through. All the while Cust. is chatting with Me ,on the roof also. I said "while I'm here,I might as well rod down the 4" main stack also " Ran out to the street pulled back about 10 Ft. ft. of rusted broken 1/4 " cable from His attempt many Years ago to open a line. This made Us laugh , and His wife a happy Gal ! NEVER DOUBT YOUR GUT INSTINCTS !