[Unclenick]

If I'm not mistaken, the basic 1907 leather sling design was standard until the canvas web slings were created for faster, more economical production during WWII, during which both kinds were produced. The leather design is by far preferred by target shooters for their greater stability and lower stretchiness.

The web slings must be designed for all weather. Nonetheless, I would use cool to tepid water and Woolite and hand wash one, being careful to avoid twisting or stretching it in the wash water.