There may have a build-up of oils from insufficient cleaning, storing in the refrigerator, or washing in the dishwasher. Fortunately, the silicone is medical grade without any pores that can harbor bacteria, so any film or bacteria is only on the surface.
First, try scrubbing the film off with a bristle brush and a detergent like Dawn Original (yellow ducks on the label).
If that doesn't work, our earth-friendly Silicone Cleaner can restore your flanges to like-new condition. It's also available on Amazon with free shipping if you have Prime (different label, same ingredients). This fabulous silicone cleaner also can be used instead of soap and water for on-the-go cleaning.
Reviewed by Diana West, IBCLC
June 10, 2021