A method for folding a liner for packaging and/or insertion into an overpack. The method may include providing a liner comprising a substantially tubular body portion and a closed top and bottom, and a fitment formed in or affixed to the top of the liner, forming a gusset in the bottom panel of the liner, forming a gusset in the body portion of the liner, and fan-folding the liner. In some embodiments, the top of the liner may be a substantially circular top panel and the bottom of the liner may be a substantially circular bottom panel, with the top panel being attached to one end of the tubular body portion and the bottom panel being attached to an opposite end of the tubular body portion. In other embodiments, the liner may be a flexible, blow molded liner, thereby having no weld seams.