Dumb question about washing wool covers?

[Judegirl]

Hmmm. If they just get soaked in wool wash and/or lanolin, and they don't get rinsed...week after week...don't they just get dirtier and dirtier, sitting in water with increasingly more pee each time??

Or do you rinse them before putting them in the wool wash?

*scratching my head*
Jude