Often, the priest at Mass only consecrates the large host for himself, and the people receive from hosts reserved in the tabernacle. At other times, there are hosts left over at the end of communion and they are added to the ciborium in the tabernacle. Very occasionally, I’ve seen an empty ciborium being cleaned out at the lavations at the end of Mass, but only because it seems to be empty by chance.
I can imagine this could get confusing, especially if there are several priests in the same parish, all celebrating Mass at different times. How do they make sure the ciborium doesn’t still have last month’s hosts in the bottom, with the newer hosts added on top, some consumed, then more added, consumed, but never completely emptied?
I’m guessing there must be more to it than that, and it’s probably something really simple, but I can’t think what. Anybody know the answer?