How to thaw a vehicle lock

The driver's side door lock on my vehicle was frozen due to water seeping in during a recent thaw. With the temperature at minus 14 C today the lock was not going to thaw very soon on its own. This re-useable handwarmer turned out to be the ideal lock de-icer. I just taped it to the door and bent the metal disk inside. Immediately the liquid crystalized and became hot. I took a short 12 minute walk and came back to a thawed lock. I recommend keeping some hand warmers handy. Just don't put them inside your vehicle because they will be a bit difficult to use when the doors won't open.