"To wash the cover" means to clean or launder the outer layer or protective sheet of something, typically a large item such as a mattress, sofa, or car seat cover.
Sentences with «to wash the cover»
You can wash the cover in the machine, eliminating any odors or stains. (earlymomentsmatter.org)
That way, I'm only washing the covers with bleach half as often. (thenaturalmommy.com)
I do hand wash the covers because I want to preserve the elastic and hook and loop. (greenmountaindiapers.com)