Caporegime
These actually look useful, where from if I may ask?
Also to re-do them, could you try the chocolate cooking method with a saucepan and a bowl of water on top so you don't burn/melt the plastic?
This is how it works from wiki
Supersaturated solution (crystallization-type)
Crystallisation types of hand warmer generate heat through the exothermic crystallisation of supersaturated solutions (typically sodium acetate) and are usually reusable. These can be recharged by immersing the hand-warmer in very hot water until the contents are uniformly fluid and then allowing it to cool. The release of heat is triggered by flexing a small metal disk in the pad, which generates nucleation centers that initiate crystallisation. Heat is required to dissolve the salt in its own water of crystallisation and it is this heat that is released when crystallisation is initiated.[3] (More can be found here.)
This type typically has a shorter heat duration of 20 minutes to 2 hours
http://en.wikipedia.org/wiki/Hand_warmer
I got it here
http://www.amazon.co.uk/Magic-Gel-R...4IJ2/ref=sr_1_1?ie=UTF8&qid=1363183943&sr=8-1
This one is large enough to last about an hour, more solution inside the packet the longer it last. It would come in useful watching football from the stand. carry two with you, one for each half. I am definitely going to put a couple in the car in case of break down.
I have tested them at lunch time and it got nice and toasty (54c apparently) and everyone in the office was impressed and they all want it now. Even the person muck me about buying it yesterday has been completely won over. It's only £3 and totally reusable, just boil them in water with a towel at the bottom it says. Or I might do a bowl sunken inside the saucepan.