Some say a couple of days, depends on the size of the colony. I have just taken a wet super off my smallest hive, half full brood box, and it was on for 5 days. Nice and clean when I took it off with just a few bees on it.
How is you forage, are bees still taking in nectar? These questions you need to address before you decide to leave on a full drawn super. If the bees don't fill and cap it before there is no more forage you end up with space that the bees have to warm during winter with no honey in them. Get the bees to fill the brood box space's first, as the queen reduces laying more space becomes available. But it's a balance this time of year. If your bees are a strong colony, and you want a fill the wet super with stores (ie brood and half) then leave the super on and start to feed so the bees can fill the super.
Steven