Milkweed Insulated Lunch Bag / Lunch Box - Vegan, Ethical, Natural Material The Lasclay lunchbox offers the rare combination of high performance, durability and sustainability with its revolutionary insulation made from milkweed silk—a plant-based material warmer than down, naturally waterproof, and hypoallergenic. Featuring an easy-to-clean dry-bag interior, it's also machine washable (cold water, delicate cycle). By choosing this lunchbox, you support the organic farming of milkweed, which promotes biodiversity by creating much-needed habitats for monarch butterflies and other pollinators, while also capturing CO2 to reduce greenhouse gases on otherwise unused marginal land​​​​​​.