This past year several of my paintings have been shipped to various locations.   Lessons learned in this regard are many.  Carefully packaging the painting for shipping is very important.  A strong commercial box intended for shipping art such as “Air Float” is expensive but well worth the cost, especially if the painting has many stops.  Museums expect this type of protection.  For a single run, prepare a box using heavy duty cardboard with two inch thick building Styrofoam insulation around all sides of the painting and frame.   The Styrofoam is light reducing costs and is resistant to punctures that may go through the cardboard.   The painting should be wrapped in brown paper and never in bubble wrap or plastic.  These melt under high heat and may stick to the painting damaging the surface.