If you're called away from the cooker - by the phone, say, or by someone at the door - take pans off the heat. It's the easiest thing in the world to forget about them.
If a deep fat frying pan catches fire never throw water over it, if you have a fire blanket, put it over the pan.
Melt the chocolate and shortening in top of double boiler over hot but not boiling water; remove from heat. Dip sections of oranges into chocolate and place on wax paper-lined cookie sheets. Refrigerate about 30 minutes.