The following scenes have been cut from some TV prints:
Both CBS and Nickelodeon removed the scene with Sylvester getting electrocuted when a coat hanger he uses to try and retrieve the can opener from the mouse snags on a power wire. However, Nickelodeon edited the scene more carefully and cleanly than CBS.
Nickelodeon also censored the scene with Sylvester trying to open the can with an axe, only for to have the blade fall off through the mail slot.
Source:: The Censored Cartoons Page