Green Safes eco-friendly compostable soup cups are made from SFI certified paperboard! This nonprofit organization is committed to promoting sustainable forest management by setting guidelines and requirements for paper merchants and manufacturers. The inner lining of these soup cups are plant-based instead of the traditional petroleum-based we are all used to. This allows them to be eco-friendly compostable. Intended for hot foods up to 200 degrees, freezer safe, not microwavable, and will commercially compost within 90-120 days.