whats the best way to get the grease off of the shoes?
There is no good way other than having them relined. Once they get oil or grease on them it soaks in and you can't get it all out. When you use the brakes the heat will draw more oil out, you can't win.
If you absolutely have to reuse them as is, first wash them with some brake clean. Then carefully, soak them is a shallow pan with white gas (Coleman fuel) and once you think they are soaked through drain most of the extra gas out of the pan, then light the remainder and the shoes on fire. Supposedly this will get more of the grease out, but nothing gets it all out.
Grigg