Clearing agents:

In my experience I CAN NOT get Cranes Platinotype to clear in EDTA. I have no idea why. I use citric acid. HCA may work just as well, but in bulk (2.5kg) citric acid is cheaper.

Also, Jorge said, "anything that dissolves iron" will work. I know as a chemist he meant, "anything that chelates iron" will work.

Obviously some chelating agents must be better than others with certain papers. Hydrochloric acid works well. You can buy it from your local swimming pool store as muriatic acid.