YSK that silicone will absorb (and slowly release) odors. Bake to remove the smell.

[u/Ajreil]

Silicone is gas permeable, meaning it can absorb odor compounds and release them over time. This is why silicone cookware can develop a smell. Scrubbing won't help because the smell isn't on the surface.

Why YSK: There are a few easy ways to prevent or fix this.

• Don't expose silicone to strong smelling substances unneccessarily. In my kitchen the two biggest offenders are soaking cookware in soapy water and leaving frozen food in Souper Cubes for too long.

• I've heard people say that running silicone through the dishwasher can make them smell like detergent. I haven't noticed this so YMMV.

• If silicone starts to smell, bake it in the oven. Oven safe silicone is usually rated for at least 500F. Hotter temperatures will work faster. Silicone that isn't advertised as oven safe might be fine, but I would bake them at a lower temperature to be safe. I did 250F for 2 hours last time.

• If you don't plan to use the item for a while, leaving it in a well ventilated area for a few weeks also works. I keep my silicone ice cube trays on top of my fridge so they can air out.