Caulk Preservation

Caulk in a tube has a tendency to dry up if not properly protected. Try wrapping the open nozzle of the caulk tube tightly with duct tape.  The tape creates a good air tight seal preventing air from getting into the tube and drying out its contents.  After putting the duct tape on and around the nozzle of the caulk tube, put the caulk tube itself in a plastic bag and tie off the opening with a tie band or something to close up the plastic bag.  I have tried other methods, but find that this method gives the best results so far.