This is a recipe from an vintage 1890s book. for cleaning black silk dresses. I haven’t tried this methods. If you attempt it, proceed with caution and not on a valuable piece of silk.
To Clean Black Dress Silks
One of the things “not generally known,” at least in this country, is the Parisian method of cleaning black silk; the modus operandi is very simple, and the result infinitely superior to that achieved in any other manner.
The silk must be thoroughly brushed and wiped with a cloth, then laid flat on a board or table, and well sponged with hot coffee, thoroughly freed from sediment by being strained through muslin. The silk is sponged on the side intended to show; it is allowed to become partially dry, and then ironed on the wrong side. The coffee removes every particle of grease, and restores the brilliancy of silk, without imparting to it either the shiny appearance or crackly and papery stiffness obtained by beer, or indeed, any other liquid. The silk really appears thickened by the process, and this good effect is permanent.