a composite , drum type container for storing and dispensing corrosive fluids comprises an inner plastic liner of polyethylene and an outer plastic shell . the end walls of the outer shell are substantially dome - shaped to add strength to the container , and the top end wall is further reinforced by an inclined offset wall , ribs , and inwardly protruding portions of the sidewall , to prevent deformation . a separate pressure plate adds to the strength of the dome - shaped bottom end wall . a recess or well in the bottom end wall and pressure plate allows complete removal of the contents of the container .