For best longevity of your seamless underwear, we recommend hand washing in cold water. When machine washed with other garments, even on a delicate cycle, the underwear may rub against abrasive fabrics such as rigid denim or zipper teeth, leading to faster deterioration. Using cold water is recommended as warm or hot water can cause the fabric's adhesive to dissolve. Following these care instructions will help preserve the quality and lifespan of your seamless underwear.