Purificatorium is a piece of linen folded several times, which is used in drying the chalice and wiping the paten during the mass. It was originally a towel fastened to the piscina, or vessel placed at the side of the altar. Only in later times it took the present simpler form — probably at the time when the priest himself drank the wine which had been used for the purificalion of the chalice and the ablution of the fingers. The cleaning of the purificatorium, as it comes in immediate contact with the consecrated forms, must, by prescription of the canon, be done by the priest himself. Its length and width must be about half an ell, and as it is exclusively employed for the ritual use, it must be consecrated and marked in the middle with a cross. The Greeks use a sponge for the cleaning of the chalice and paten-a custom mentioned by Chrysostom (Homil. in Epist. ad Ephes.). — Wetzer u. Welte, Kirchen-Lex. s.v.