Here is my method: 1)Purchase a new box that is about 4 inches larger in all dimensions than the original. 2)Purchase from Home Depot, one package of 16" X 48" sheets of insulating styrofoam. Cut these sheets to size, in order to line the inside of the new box on all sides. 3)After you line the box, pour about 3 inches of peanuts on the bottom, and then place the original box inside. Pour more peanuts in, pushing them down the sides, and finally topping off. 4)Put your styrofoam "lid" on, and then seal the box.
It takes some time to do this; but to me, avoiding the hassle that would be involved with a damaged package is worth it.