Thanks to the research efforts of Linda Gleysteen, here is information of what it might well have meant that St. Maura prepared the wax for the altar of her church, from a discussion of The Holy Mass (Latin Mass):

As explained in Appendix I, 18: “Altar Table Coverings (one wax and three linen cloths cover the altar table. The fourth or top one of linen frequently edged with lace hangs down over the side of the altar to the floor)”

Also, from the Diocese of West Texas Altar Guild Handbook

“The cere [or wax] cloth is a protective cloth that goes between the fair linen and the frontal on the altar. It protects the linen of the frontal and the altar from wine spills. A felt-backed, white vinyl sheet, cut to the size of the top of the altar and placed vinyl side up just beneath the fair linen, has been found to be very effective.”

No doubt, Maura was involved with ensuring the cere cloths were just what they needed to be!

Thank you, Linda Gleysteen!