ncyue

I purchased a several years old Proform Tour de France 5.0. At the lowest position the seat is a little high for me. It seems that the long seat tube hits something at the bottom and can't go any lower. I would like to cut it about 1.5 inches shorter. It is oval in cross section so a pipe cutter will not work. Will any hacksaw work, or do I have to have a special blade? Any hints on how to cut it straight other than holding it? It will be inside the seat tube so aesthetics is not that important.