https://www.scientificamerican.com/article/plane-deicer-lasts-several-thousand-hours/

“A recent development that increases flight safety by keeping airplane propellers free of ice consists in painting or spraying the propeller blades with a chemical lacquer called Icelac. Black in color, it has a consistency something like that of glycerine, and paints or sprays freely to give a shiny, tacky surface. A satisfactory icing protective surface is maintained for several thousand hours.”

—Scientific American, April 1945