Originally Posted by philsweeney
Adequate clearing will be indicated by the fact that there is absolutely no stain left in the areas of the paper that were sensitized but that received no exposure. If there is any stain at all your clearing was inadequate. Fogging could also cause stain but assuming that you are drying your sensitized paper in the dark, or in very low light, this should not be a problem.
For a more methodical approach see the section on how to verify clearing at Jeffrey Mathiias' site. H