Shown in the pics below are good views of the paper towels wetted with water and wrung out damp before applying to the case surface to dampen the fibreboard right through the old "tolex" covering, which will make the fibreboard reconform to the clamp molding. The ability to do this with aged case coverings is highly suggestive that these old fibreboard cases must be resealed with a spray on finish to make them reasonably water resistant again. ~~~~~~~ If a person doesn't know or understand the dynamics of spraying down successive very light coats of finish, so that the case's fibreboard and covering doesn't become wet and distorted, then the job is best left to someone who knows how to do it. Most reputable amplifier retorers know what sprays work good on coverings, as do luggage repair shops. And automobile paint shop that knows how to restore vinyl car tops would also understand the process once they see an old fibreboard case. ~~~~~~~ Should someone desire to give a try, then they can email me and I can provide detailed instructions.