that touched the pot
that touched the food
that touched the liquid
(that might or might include blood)
but if uncertain if object is impure. just ask it! they are the only ones who would really know what happened to it
(a chain of impurity contagion is discussed. liquid needs to be present in order for the impurity to flow form one object to the next. and a repeat of the discussion if blood from a pure animal that is collected and used in the sacrificial procedure counts as a liquid that makes something impure. but the page begins with a statement that if the purity status of an object is uncertain and was due to human hand, then ask the object...)
