Well, this was a little too vigorous a reaction to be used in making hand warmers, so we decided to stick to slaking lime. The best reaction for use in our hand warmers was the 'slaking' of lime.

But not so with the Go Warmer. This lozenge shaped device is not ... You can hold in in your hand, put it in your pocket, maybe even sit on it if you’re particularly daring.

I used to think hand warmers were always soft and squidgy gel patches you'd stick in your pocket and press the button - and once you'd used it you'd have to wait and submerge it in hot water to ...