The next source could be your hive!
Some beekeepers will place their honey supers back onto the hive for a week. This will give the bees enough time to clean the comb in order to begin building up the honey stores again. Remove your top but leave your inner cover on. Place your 'dirty' frames above your inner cover and place the top back onto the hive. Give it close to a week before trying to remove the supers.
If you do not want to go back into your hive (you called it quits for the season and you want to leave them closed up) you can place the supers out in the open for your bees to clean up. You will want to keep the supers at least 200' away from your bee yard. Again, this can cause a robbing frenzy that can lead back to your hives... so the further away it is, the better.