Re: How do I clean Sippy cup valves?
I toss them in a cup of bleach and let them sit for a few minutes, scrape out anything remaining after sitting with a very small brush (I've also been known to use the tip of a paring knife because it's small enough to reach right into the really tight spots) then run it through hot water. The bleach kills the mold that permeates the plastic, not just growing on the external surface. HTH's!!