I just saw a video of someone aligning a bmx frame with a hammer. That frame must have been made out of really thick tubing, because it didn't seem to dent the tubing. But unless you see that one of the stays is slightly bent, you could bend the long seat stay a little. I'm not sure I would try it. Moving one of the dropouts by un-brazing and re-brazing is an option if you are repainting, but it doesn't seem like it would be worth it on a beater.