This historical tidbit comes from a page designed by J.R. Burrows & Company, Historical-Design Merchants about historic carpet cleaning methods. One sees in films carpets being hung outside on a line and beaten with carpet beaters made of cane.
Some carpets were fitted and hard to remove. In such instances, druggets, or hard-wearing canvas cloths, came to the rescue.
One of the most common strategies of keeping carpets clean in the early nineteenth century was to use druggets, heavy woolen goods spread under tables to protect carpet from spills. They are sometimes called crumb cloths. In addition to dining rooms they were used in other areas of heavy wear. E.V. Rippingille painted The Young Trio in 1829 showing a drugget protecting carpet in a parlor where children are at play. - Historic Carpet Cleaning Methods in the Nineteenth and Twentieth Centuries
You can clearly see the drugget underneath the table in this classic print.
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