More on the purity/impurity stringencies... Trying to make sense of the list of them, by their numbers. One who carries something that has impurity because of the way it came in contact with someone who was impure can also carry terumah, but not kodshim. This stringency is based on a one-time occurrence of things going wrong. Also, another stringency focuses again on the possibility that an am ha-aretz would render a chaver's vessels impure - including the very unlikely case. Plus, the final stringency of the daf, that has support in a biblical verse, unusually here.