You know you are getting to the old stuff if it starts turning blackish/dark/greenish a few days into the cleanse. The color will change from food colored waste.
If you stay on it, eventually you have formed bowel movements again while still taking the same dose, so that implies that it does do some real cleaning.
I think this is a good product to start cleaning and loosening - but should not be relied upon as the 'end-all' .. but the beginning.
I am on it now, and plan on doing follow up cleaning just after I am done...either psyllium or maybe colonics (not sure yet, I like the OXY because it cleans from the top down, instead of the reverse..)..
and making permanent diet changes.