Compostable plastics don't compost if you just throw them in a compost heap, you need to compost them in high-temperature conditions.
Well that is disappointing. I feel like that should be specified on the bag instead of alleging it is generally compostable like a brown paper bag.
yeah I mentioned municipal compost because they can get the compost temperature way higher than we can at home scale. It should break down in the big compost piles they have