The same thing happens here in the states -- lots of Canadian coins and some other random foreign stuff ends up in circulation. When I was in college in the 90's (back before everyone paid with debit/credit cards) I worked nights at a grocery store, and I used to pick out the Canadian coins and put them in a mason jar at home. After seeing so many of your posts I was thinking that jar must still be around somewhere...
After some hunting I managed to find it. It's overwhelmingly pennies, but a lot of everything else too. For pennies there were 5 King George VI cents with a couple from before 1948, about twenty with a younger QE II, 4 of the peace cents and 3 of the 1992 commem., out of around 200 pennies.
About the only other interesting thing was a couple of 12-sided nickels, one with KG VI and the other with the younger QE II. Some of the quarters are from the late 60's and could have a slightly different metal composition, not sure.
At any rate, I set aside all the interesting stuff, which didn't even amount to $1 face value. I'll probably deposit the rest at the bank when I'm back in BC this spring. I know that's cringeworthy to coin collectors, but it would be cost-prohibitive to mail it from the US, and everything is well-circulated so I doubt there's much value there. At least I'm repatriating it all back to Canada!