Get your sharpie out, Live Long and Prosper. There are a lot of ways the old fivers can be changed in to famous people, and now with the sad passing of Leonard Nimoy, a lot of 'Spocked' bills have been popping up. Because of this, the Bank of Canada has pubicly stated that you can
do this and it's not illegal! They also put out the warning that some businesses may refuse them though. I don't know about you, but I'd probably keep a Spock 5 and not spend it.