Break away panels, devices and methods of using the breakaway panels with grid scored patterns for fire extinguisher cabinets which can be made for small, mid-size and large size fire extinguisher cabinets, and easily resized when needed. Three novel panels each having novel vertical and horizontal scored lines running throughout the panels and be located on the inside surface of the installed panels. An installer can easily break off upper and/or lower and/or side edges of the panels in order to resize the panel to fit almost any size fire extinguisher cabinet. The scoring lines can be accomplished by a router. Alternatively, the entire panel and the scored lines can be formed from injection molding.