There is an article published by the United States Conference of Catholic Bishops entitled “The Care and Cleansing of Altar Linens.” You can read it at
usccb.org/liturgy/innews/032001.shtml (scroll down the page). The section on “Purificators” reads as follows:
"Purificators are customarily brought to the altar with chalices and are used to wipe the Precious Blood from the lip of the chalice and to purify sacred vessels. They should be white in color. Whenever the Precious Blood is distributed from the chalice, poured into ancillary vessels or even accidentally spilled, purificators should be used to absorb the spill. The material of purificators should be absorbent and easily laundered. The purificator should never be made of paper or any other disposable material.
“Because of their function, purificators regularly become stained with the Precious Blood. It is, therefore, essential that they should first be cleansed in a sacrarium and only afterwards washed with laundry soaps in the customary manner. Purificators should be ironed in such a way that they may be easily used for the wiping of the lip of the chalice.”
So, while nothing is said in the article about how many times a purificator is used between launderings, it is obvious that purificators can contain the Precious Blood, and should be handled with due care. If they have to be cleansed in the sacrarium for this reason, surely we should not be leaving purificators stained with the Precious Blood lying around unattended! What does your pastor do with them between uses — does he leave them in the tabernacle? I doubt it!
At our church the purificators are rinsed in the sacrarium immediately after each Mass, hung to dry, and then kept in a container to be laundered once a week.