A method of forming a rounded edge in a container made from a substantially flat blank of a stiff paper or card material, comprising the steps: forming a plurality of substantially linear grooves in a region of the blank intended to form said rounded edge, said grooves extending substantially parallel to an axis defining a center of curvature for the rounded edge; and bending the grooved region of the blank about said axis such that a substantially rounded edge is obtained by virtue of bending deflection distributed over the plurality of grooves; wherein the step of forming said grooves comprises debossing a first surface or face of the blank, wherein the debossing comprises pressing a plurality of substantially linear tool element s into said first surface or face of the blank, while an opposite or reverse surface or face of the blank is supported on or against a flat or smooth counter surface, wherein each substantially linear tool element comprises a ridge element raised or projecting from a base surface to deboss a corresponding groove into the first surface or face of the blank, wherein a height (h) with respect to the base surface of the plurality of substantially linear tool elements is larger than a thickness of the blank such that the base surface does not engage the first surface or face of the blank as the grooves are formed, wherein the raised or projecting ridge elements each have a tapered transverse frusto-conical cross-section with a blunt or flat outer edge region spaced apart with a pitch (p) in the range of 0.3 mm to 1.0 mm, wherein sides of the raised or projecting ridge elements form an angle of in the range of about 90° to 130° with the base surface, wherein the edge regions have a width (w) in the range of 0.1 mm to 0.5 mm, wherein the number of grooves in said region of the blank intended to form the rounded edge is in the range of 3 to 20, wherein a spacing or a pitch of the grooves is in the range of 0.3 mm to 1.0 mm, and wherein a depth of the grooves is in the range of 0.1 mm to 1.0 mm. forming a plurality of substantially linear grooves in a region of the blank intended to form said rounded edge, said grooves extending substantially parallel to an axis defining a center of curvature for the rounded edge; and bending the grooved region of the blank about said axis such that a substantially rounded edge is obtained by virtue of bending deflection distributed over the plurality of grooves; wherein the step of forming said grooves comprises debossing a first surface or face of the blank, wherein the debossing comprises pressing a plurality of substantially linear tool element s into said first surface or face of the blank, while an opposite or reverse surface or face of the blank is supported on or against a flat or smooth counter surface, wherein each substantially linear tool element comprises a ridge element raised or projecting from a base surface to deboss a corresponding groove into the first surface or face of the blank, wherein a height (h) with respect to the base surface of the plurality of substantially linear tool elements is larger than a thickness of the blank such that the base surface does not engage the first surface or face of the blank as the grooves are formed, wherein the raised or projecting ridge elements each have a tapered transverse frusto-conical cross-section with a blunt or flat outer edge region spaced apart with a pitch (p) in the range of 0.3 mm to 1.0 mm, wherein sides of the raised or projecting ridge elements form an angle of in the range of about 90° to 130° with the base surface, wherein the edge regions have a width (w) in the range of 0.1 mm to 0.5 mm, wherein the number of grooves in said region of the blank intended to form the rounded edge is in the range of 3 to 20, wherein a spacing or a pitch of the grooves is in the range of 0.3 mm to 1.0 mm, and wherein a depth of the grooves is in the range of 0.1 mm to 1.0 mm.