Warmlii is reviving the Swiss tradition of using cherry stones for therapeutical purposes by making eco-friendly thermal pillows that can be used hot or cold to alleviate aches and pains.warmlii pillows are 100% natural and plastic free, they are made with organic cotton fabric, filled with cherry stones and wrapped in biodegradable packaging. Properly cared for these comforting pillows can last you for years. All pillows are handmade by Bee in her little home studio in Bristol.