Many folks confuse "Plumber's Putty" and "pipe joint paste" (aka "Pipe Dope") Two different products for different uses. Plumber's putty is a clay-like material that is used to form a seal between sink strainers and sinks. Pipe Dope is a thick goo that is brushed on pipe threads to seal a joint. Some plumbers prefer Teflon tape instead of pipe dope, some prefer using both tape and dope. I think it's largely a matter of personal preference. When I was a kid on the farm in pre-plastic pipe days, we used the muck in the bottom of oil paint cans on our galvanized pipe fittings. It was probably full of lead, but it seemed to work.