I replied to your question on how to get rid of your I-94, but your question was deleted. SO, here's your answer:
I work for CBP and this is what you should do:
(1) Go to this link: http://www.cbp.gov/xp/cgov/toolbox/ports/
(2) Find the State that you crossed INTO from Canada
(3) Find the Port of Entry that you crossed into
(4) Write down the address of the Port
(5) Mail your I-94 to that Port of entry
Do this before you leave! If the Port does not get your I-94, the computer system will think you are an Overstay and you will have problems coming back to the USA in the future.
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