My tool of choice here would be the Ryobi 22" chainsaw with the oiler turned up high

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If my chainsaw was out of gas I'd use the cutoff wheel and files/sandpaper as the other gents have recommended. By the time you are done with your project you'll find that you've become a skilled surgeon with your cutoff wheels. I always know that I'm nearing the end of a project when my 3rd dremel is dying.
Here's what I do.......YMMV:
I took a 5" X 1" ID pipe nipple and beveled one end to a sharp edge. I use this 'tool' along with a good hammer and a block of oak to make 1" cut-off wheels for my dremel out of the SUPER STRONG 4" or 5" cut-off wheels for the larger tools. Just drill a small hole in the center(s) after you make 10 or so. They CUT and they LAST 20 times longer than the ones you buy for your dremel....plus they will NOT break.......and you'll save a bundle of $$$. It only takes a couple minutes to make 'em. It would take me about 5 or 6 of the 'cheap' dremel wheels to make the cutout for one light......I'd use one of the super duty homemade wheels and have enough left over to cut out the light on the other wing.