Abstract: A container for bulk material, having side walls and a bottom, in combination with an insert of flexible material. The insert has side walls of the same shape as the side walls of the container and fits removably in the container. The insert has a tubular core spaced inwardly from the side walls of the insert, this core being of flexible material and having connecting elements that extend between the core and the side walls of the insert. The insert has a filling aperture, whereby during filling of the container with bulk material, the bulk material connects initially in the core and presses the flexible material of the core radially outwardly into a cylindrical shape.