All of these suggestions are good. The bottom line is to avoid any contact with a solution that has a pH over 7 before the unused ferric has been cleared out. In my area, this means a water rinse after the developer is out of the question. For me, a disodium EDTA bath followed by two HCA baths will clear most papers. For some really stubborn papers, i keep a bottle of already dilute phosphoric acid (note: has some nasty fumes) that I can whip out for the last bath if necessary. One useful tip is to view the paper with a light shining through it from the back after that last bath. Examine the highlight areas closely for any hint of a yellow tone. If you see any, you haven't adequately cleared the paper, and may need a longer soak or a different bath such as the phosphoric acid I mentioned earlier. Dilute muriatic acid (HCl) will work as well, but is noxious to breath (much worse than phosphoric) and will corrode any metal in your sink area in no time. I stay away from it because it because of its nastier side effects.