According to Robert Gray in the Colon Health Handbook, you can recognize stools containing old mucoid matter (mucoid plaque) by an unusually strong odor, an intermingling of different shades and textures, if they're atypically dark in color, or have shapes other than smooth and cylindrical. If you're having trouble recognizing old mucoid matter, he advises, drink carrot juice along with the colon-cleansing product you are taking (refers to psyllium-based products, probably not Homozone-type products) while keeping away from spinach and othger green leafy vegetables high in oxalic acid. This will usually turn the fresh feces a bright orangish brown, making them easy to distinguish from the darker old feces (mucoid matter, or mucoid plaque). If no portion of the feces become a bright orangish brown as a result of drinking the carrot juice, this indicates that old feces are still present and are dissolving thoroughly enough to become homogeneously mixed with the fresh feces.