Breasts are sold sometimes complete, or as shown by the dotted line, halved. The following diagrams deal with the half that has the bones in, left and right sides.
With a sharp knife (A), cut back the flap made by the diaphragm, until 3-4 thin white bones are visible.
With the point of the knife (B), lift out the first 2 or 3 bones, which will be easy. Leave the more firmly attached ones till later.
Cut along the joints between the ribs and the breast bone, marked by knife (C), along the dotted line. Remove each rib as shown by knife (D).
Make another cut along the breast bone as shown by knife (E). Remove the remaining flexible ribs and any other bones.