Examples include cork, cotton, recycled tissue/clothes, hemp, flax, coco, wool, lightweight wood fiber, cellulose, seaweed, etc. Similarly, many plant-based waste materials can be used as insulation such as nut shells, the cob of corns, most straws including lavender straw, recycled wine bottle corks (granulated), etc. They usually have significantly less thermal performance than industrial products; this can be compensated by increasing thickness of the insulation layer. They may or may not require fire retardants or anti-insect/pest treatments. Clay coating is a nontoxic additive which often meets these requirements.