I found a lot of parasites by using the plastic fork method of squishing the stool against the side of the toilet bowl. parasites are often completely mixed in the stool. Stool will squish and dissolve in the water. Worms, flukes, tapes, etc. will remain hard and not dissolve. So my rule was, remove anything that did not dissolve. Sometimes you can't identify the parasites or separate them from unprocessed food until you wash them off.