Small Towels How Do They Make Those Hot Towels In The Airplanes?

How do they make those hot towels in the airplanes? - small towels

If you have ever been in, or a flight from Singapore Airlines, which serves hot towels, you will generally spend at the time of departure and before .. those little white towels are warm and very hot, remove the passengers to be on their faces too fresh.

I love these towels .. How do I get my hot towel like that? Thank you.