How to Open Oysters With Heat

First and foremost, if your oyster is open and doesn't close when disturbed, discard the stinker as it's dead and gone.  Dead shellfish quickly develop a toxic bacteria build-up.

Now, any heat source will open your oysters.  If you want to use boiling water, place oysters in a saucepan.  Notice that the oyster has a rounded half of it's shell and a flat half.  place the rounded half on the bottom of the pan and fill with water to a level just under the meeting point of the two shell halves.  Remove oysters, bring water to rolling boil and replace oysters carefully with long handled tongs. Cover.  It should only take 3-4 minutes for the oysters to open.

Fire can be used as well, in a few different ways.  One technique, if you happen to be on the coast, is to build a fairly large fire and burn it until there is a good, hot coal base.  Then cover this coal base with a layer of seaweed (kelp is best).  You can then place the oysters on top and they should steam open.  Alternatively, scrape a place in the sand under the coals and place shellfish directly on the sand near the remaining coals.  A charcoal BBQ also works fine, and simply requires that you place the oysters on the grill.