Also discussed here:
https://news.ycombinator.com/item?id=30023681
We now use "Wheat Bags" ... cloth bags, usually cylindrical, filled with wheat. Heat in a microwave and use where one would use a hot-water bottle, but without the danger of a leak.
https://news.ycombinator.com/item?id=30023681
We now use "Wheat Bags" ... cloth bags, usually cylindrical, filled with wheat. Heat in a microwave and use where one would use a hot-water bottle, but without the danger of a leak.