I did a nasal snuff tutorial for YouTube. These are by no means the only correct ways to take snuff, in fact my ways are a little unorthodox, but they work quite well, particularly the way I use the tube sniffer, which causes people a lot of headaches and is shown incorrectly (making lines and snorting) on a lot of channels.
http://www.youtube.com/watch?v=PEDux-U5dfY
http://www.youtube.com/watch?v=PEDux-U5dfY