I am definetly not an expert but here is what I done and it seems to have worked.
We had an old fogger, in the shed, still full of insect spray of some kind. I washed it inside and out with dish soap. Then run vinegar through it and let it set for a day, with vinegar inside. To find out if this was successfull I put in mineral oil, wnet over to the window in the hog barn and foged the flys. First the remaining vinegar foged out. Then the oil. I foged the flys 4 times and they did not die.. All apeared well so I foged one hive a little. , 2 seconds. Still all was well so I foged them a little more. Half hour later I foged the other hive. I only have 2 hives. 2 days later they show no ill effects so I assume all is well. Just passing this along for anyone interested. I don't know what kind of insecticide had been in the fogger.