You mention that if these scholarships are not used they may go away.
I'll point out that even if I take most of those scholarships, the extra tution for going to the US from Canada, and increased living costs are much more expensive than paying for the whole thing here in Canada. I've gone through the whole list and there is grand total of 1 scholarship worth my time to apply for.
They are great scholarships when they cost you more money when you win
Plus, how many are for arts colleges advertising on a Sci/Tech site?