.. wrote:
Grunff wrote:

Lobster wrote:

My daughter was given a 'handwarmer' for Christmas, comprising a
plastic sachet about 3" square and filled with some form of gel.
Also side is a small bit of bent metal; you bend the metal piece so
it 'clicks' and bends in the opposite direction, which initiates a
reaction causing the gel to solidify over a period of several
minutes, giving out substantial heat. Later you bung the thing in a
pan of boiling water for 20 mins to melt the solid back to a gel and
reverse the reaction. Not exactly environmently friendly use of
energy, but hey...
I /so/ want one of them :-)

where can I get one ?

2 for £1.99 at Aldi, I think - if not Aldi, then Lidl. These
are selling right now. 55 deg. c for "up to an hour".