My dad found a bunch of old notes (do you call them bills?) in his room, which are from the Birds series. They are all $20 or smaller. Most have writing and lots of folds / creases so are of no numismatic interest over here.

Can I still spend these on my next trip to Canada which will potentially be this summer, but might not be until next summer, when all of your money will be plastic? If not, how can I as a visitor get them changed to polymer notes in Toronto? (Will be coming for only a few days for family events and I think the hosts will be too busy to bother bringing me to their bank.)

PS. I know I can just give pennies to charity, but will I still be able to use say 10 pennies in one go without pissing people off?

Just how old are they? They may be worth more than face value.

Those old notes are still legal tender and any bank should be able to exchange new notes for them.

As for pennies, the rule is that you can still use them as long as you round up/down to the nearest $0.05. However, I've found some stores to be quite unintelligent and have just refused to accept any pennies. It's on a case-by-case but if you're going into a bank anyways, you can exchange those pennies for nickels and dimes.

So are you saying that any bank will swap $200 old to new notes from a foreigner who has no relationship with them?

Yes, I believe that's what previous poster is saying. The branch may ask whether you have an account but cannot refuse to accept the bills as they are legal tender as is noted in this FAQ from the Bank of Canada:

http://www.bankofcanada.ca/banknotes/bank-notes-faq/

All notes issued by the Bank of Canada since 1935 have legal tender status and retain their full value. If you don�t know how to check notes from past series, exchange them for newer ones at your local bank.

1 (not in the Birds of Canada series, but maybe you have some) and 2 dollar notes can generally find a new owner quite easily, even if folded and creased., if you have any in your pile.

If you can locate a private buyer for a large quantities of copper pennies you can get more than 1 cent for each of them

As tcook said, yes. I often take the stack of $20s from the ATM, walk to the bank teller, and have him/her change it to $50s. And no proof of a bank account needed.

The "Birds" series really aren't that old and I get them as change every-so-often. You really don't even need to change them into "new" bills.

I would be very surprised if they didn't. (Assuming the banknotes are not fake.)

However, I would think that the bird series don't even need to be exchanged, but can be used. I received a $20 one last year or maybe it was the year before.

$1 and $2 might be an issue at the supermarket etc. because they aren't set up for those. Me, I would take them happily. and I would think that you would make a smart waiter/waitress happy if you added it to their tip. :-)