well.. unless you crossed the mafia... then, you just vanished.
If they wanted to do a disappear, It was either into a drum full of concrete, and into the Lake, or the Illinois State Barge Canel, or a fast trip to the Gary steel mills, and into a blast furnace. Tony Spilotro was beaten to death, and buried in an Indiana corn field.
If they wanted to make a point, it was public. The Outfit would stick the body in the trunk of his own car, and park it at O'Hare long term parking. The Chicago PD would cruise slowly through the lot, in the spring, with the windows rolled down, sniffing...