Trade in devices need to be in working order unfortunately so if they're broken you'll need to try and sell them privately to offset the price of your next phone. Also you'll get much more for working units selling them privately than you would through trade in. Try Kijiji or Craigslist to sell them, they usually sell pretty quick if you price them slightly under what others are selling for there.
You will usually get twice to three times as much than the trade in value if you sell them privately. If you still wish to trade in a working device then you just bring it to your local Koodo kiosk and they will check it out and give you a value of what they will give for said device.