Well by holding it up to a sheet of glass, I was able to figure out where the bends were and how bad the bends were. I then placed the rim on a sofa and pushed hard using my weight (you will be surprised at how much weight is needed) on the rim. I placed the rim with the bends on the arm of the sofa and pushed hard to reverse the bends. It works but it is trial and error. Works best if the wheel has a single bend.

Push,tweak, check. Over and over for a bunch of minutes.