This page is credited in full to Dave Cushman who created it. His voice is expressed in black colour text and any additions or comments in blue belong to myself. Credit: Dave Cushman’s website.
This version is often attributed to a man called “Wioblett”.
It can be used heated, in boiling water or by resting on a hot plate.
It can also be used cold following a hair drier. (This tip from Michael Hurley.)
Never had any success with this kit. I use a battery charger. 😉