Welcome and you have come to the right place for good advice. If you can post a few pictures of what you have, picture of bag, side of the rolls, it will tell us a lot more than most words. Depending on if the rolls are original or hand rolled they can be worth more/less. If you can see the ends, they might be unopened rolls (don't open them) and will be worth more than rolls that were done by hand.
1st step: Don't open the bags, they will be worth more unopened. (Post some pictures before opening any rolls)
2nd step: Don't clean anything
3rd step: Don't move the bags around
4th step: Decide what you want to do with them (keep/sell/or some combination)
5th step: Check your expectations
I'm not sure what the going value for an original mint bag of pennies is, but it is probably not huge. If you look at site like http://www.coinsandcanada.com
it is easy to get excited, you'll see something like a MS-63 1961 penny listed at $1.75 and think that you have a small fortune on you hands ($1.75 x 6000 coins x 5 bags = ~$50,000), unfortunately that is not realistic or that easy. One of our experienced members indicates that he rarely pays more than $100 per bag for a $60 bag. Basically most coins in the bag will be worth $0.01. And the nice ones that are left can be very difficult and/or time consuming to sell.
Here is another thread you can take a look through.http://goccf.com/t/247668
1. Taking them to a bank (face value), easy but will realize least amount of money as they only give face
2. Take them to a dealer, they will offer you some % of current market price (they need to make money as well), but it will likely be close to face value, if they even want them (unless there is something interesting in the rolls)
3. Try to sell locally/online (eg. ebay), will get you more, but can be time consuming
4. I think you have to make about 50 posts, but you can try to sell on this site, there is probably someone is your area here that would be interested in all/some of the collection. At least I know I would be, I am in Vancouver and have always wanted to search through a bag or two.
In short, post some picture of what you have, checkout coinsandcanada.com and check back on this forum as you will get some good advice.