Washboard
A washboard is a utensil with a ridged working surface against which laundry was rubbed during hand washing. The Norwegian Academy Dictionary describes corrugated metal or glass plates in wooden frames, as well as older wooden versions. The term describes a function rather than a single material or manufacturer.
Washboards illustrate household work before washing machines took over much of the task. A simple or worn appearance cannot securely date an individual board. Store norske leksikon notes possible confusion with felting boards. Ridges alone are therefore insufficient to determine the function of an unfamiliar textile tool.
When buying, describe the working surface and frame separately. Look for cracks or chips in glass, rust or worn-through sections in metal and loose wooden joints. Record any maker's names, printed text and indications of a replacement plate. Preserve legible markings during cleaning. A name in advertising decoration is not automatically the factory that made the board itself.
Sources: Ingun Grimstad Klepp, OsloMet: vaskebrett i Store norske leksikon; Det Norske Akademis ordbok: vaskebrett.