Before you throw away the containers look for any "best before .....". I´ve had a couple of old containers with both resin and hardener left. I opened the hardener container and was nearly knocked out by the intense vapour. Talk about bad breath!!! This smell was corrosive and lasted for a long time. All left containers was disposed of as dangerous garbage for destruction at the environmental station along with the chemical certificate.
Keep your smaller containers as cold as possible and in the dark.