Stove blacking is a type of polish or coating used to clean and protect the surface of cast iron stoves. The blacking is typically applied as a liquid or paste, and then polished to a shine. It helps to protect the stove from rust and discoloration, and can also improve the stove’s heat efficiency.
It was Almanzo’s job to apply blacking to the stove when his parents were away, which ended with Almanzo inadvertently throwing the blacking brush against the white and gold wallpaper in the parlor, staining the paper with the blacking paste on the brush, in the “Keeping House” chapter in Farmer Boy.
As cast iron stoves have fallen out of favor, blacking polish is not as readily available, but is now sold under the name of “stove polish” instead of blacking.