While having shower curtains the last 6 years, I have never thought to wash my shower curtain liners. I always just bought a new one when it was dingy.
I washed our shower curtain - warm water, no fabric softener, and regular detergent. It came out looking brand new!
Before washing, it was dingy on the bottom and had black splatters from my hair dye.
I always love finding more ways to be frugal! :D