is it always necessary to re-roll after each dunk?
If the side if a cap looks like it has a bruise, a dark colored contusion that seems a bit softer than the rest of the cap, is that contaminated?
Those "tumors" you see are most often the result of the cap touching petrochemicals of some sort there is a term for it that I just can't recall. At least I it looks sort of like that. Usually you see some of the gills turned out through it.