Re: How long can a capped super last before extracting?
In Washington? I'd wrap them up in a plastic bag or put them in a plastic tote and keep them in my basement. This late in the season I don't see any problem. I have had frames out in a swarm trap since last April and just now I am starting to see a few larvae and hive beetles. I shook them out on the ground and put the frames back in. I am going to store them through the winter that way.
Take a picture in a week. I want to see this slime you speak of.
Zone 5a, Practicing non-intervention beekeeping