Underneath the window rubbers, the metal lips can rust away. In the case of the front screen this rust can spread to the top scuttle. The top scuttle also rusts if the drain holes are allowed to become plugged so that water cannot escape. To deal with rusted window lips, simply grind out the rot and butt weld in two thicknesses of steel, giving the insides plenty of protection with weldable zinc paint beforehand. Top scuttle repair panels are not, at the time of writing, available, leaving the option of fashioning a repair panel (which can be done with a few basic panel beater's tools) or cutting the section out of a scrap shell. In either case, butt weld the new steel in very carefully to avoid distorting the scuttle.