Many relics of Eliza and Stephen Jumel survive, from personal letters to the wallpaper that decorated their home. The fact that the letters and wall hangings were made from rag paper—used in Europe and and the United States until the mid-nineteenth century—was a big key to their longevity. Richard Campbell, writing in 1747, provides a very clear description of how paper was made during the centuries when it was manufactured from cotton or linen rags rather than wood pulp:

"The Rags are picked, separated into Parcels, according to their Fineness, washed and whited; then they are carried to the Paper-Mill, where they are pounded amongst Water till they are reduced to a Pulp. When they are beat to a due Consistence, they are poured into a Working-Tub, where there is a Frame of Wire, commonly called the Paper-Mould, which is composed of so many Wires laid close to one another, equal to the Dimensions of the Sheet of Paper designed to be made; and some of them disposed in the Shape of the Figure which is discovered in the Paper, when you hold it up betwixt you and the Light.
[Campbell's "Figure . . . discovered in the Paper" is what we call a watermark today.]
"This Frame the Workman holds in both his Hands and plunges it into the Tub, and takes it quickly up again: The Water runs through the Spaces between the Wires, and there remains nothing on the Mould but the beaten Pulp, in a thin Coat, which forms the Sheet of Paper: A Flannel-Cloth is laid upon the Top of the Mould and the Paper turned off upon it; then they dip as before, and continue to supply the Vessel with fresh Matter as it decreases. The Flannel Cloths suck up the remaining Moisture, and the Paper after some time will suffer to be handled and hung up to dry in Places properly fitted for that purpose."
Source: R[ichard]. Campbell, The London Tradesmen: Being a Compendious View of All the Trades, Professions, Arts, both Liberal and Mechanic, now practiced in the Cities of London and Westminster (London: T. Gardner, 1747), 125.
Workman holding a paper mould, letting the water drain from the paper pulp. 18th-century engraving.
Workman holding a paper mould, letting the water drain from the paper pulp. From Diderot & d'Alembert, Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, 1767, vol. 5, “Papetterie,” detail of plate 10. University of Michigan Library.
Eighteenth-century engraving showing workers hanging paper to dry.
Workers hanging paper to dry. From Diderot & d'Alembert, Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, 1767, vol. 5, “Papetterie,” detail of plate 12. University of Michigan Library.