In a molded collapsible solution container, which container defines a chamber-defining body portion wall having an integral neck portion and a shoulder portion at one end thereof, and tapering from said shoulder portion progressively along a major portion of its length to a flat, sealed end portion at the end of said container opposite said one end, said container also defining a pair of opposed gusset portions adjacent said shoulder portion at opposite ends of said shoulder portion, said shoulder portion defining opposed shoulder edges extending between said gusset portions, and a pair of opposed lines of flexing weakness defined in said collapsible solution container and exhibiting an arcuate cross section which extends inwardly of said container, said opposed lines of flexing weakness being positioned on each side of the container in generally parallel relation to said opposed shoulder edges, said opposed lines of flexing weakness being longitudinally spaced from the shoulder edges by a distance which is proportioned to cause said opposed lines of flexing weakness to enter into abutting relationship with one another as the container collapses inwardly about said opposed shoulder edges, said distance between each opposed shoulder edge and an associated line of flexing weakness being more than one half of but less than the total spacing between the opposed shoulder edges, whereby the abutting lines of flexing weakness inhibit further collapse of the container under the pressure of suction, to slow their rate of subsequent collapse.