I am going to treat with an oxalic acid drench this fall/winter. I have read to wait until the bees are broodless and even clustered, do you wait until winter and treat on a warmer day? I would think cracking the hive open and dumping fluid on the bees in cold weather would be detrimental, but I have no experience there so I don't know. What are your thoughts on timing? I am in Eastern Washington.