I'll have to try the rubbing alcohol bit. I hate using the wasp killer, but I'm allergic (was stung by 2 hornets a few years ago & I swole up like a balloon!) so I can't really take too much of a chance. They have a real bad habit of making nests inside the grill, too, or the charcoal smoker. But I found they leave my birdies (I love feeding the goldfinches) alone if they have their own source of water.
