Little Hotties Hand Warmers
These are awesome. They aren't very expensive. They are safe and environmentally friendly. They do not require electricity and cannot burn you. They don't seem to give off any odor or fumes when activated, something I am extremely sensitive to. If you are worried about homeless people in your area in winter, in addition to a hot meal, jacket or similar, give them a ten pack of Little Hotties. These have really made a difference for me on cold nights.