Discovered a good method to get rid of glue smudge without losing fibers. If you scrape with a knife or razor blade, it often happens that the glue takes some wood with it, which you should try to avoid. This is what it looked like inside the guitar. A desperate attempt to get it playable with small pieces of wood, on one it said “BAUHAUSE” 🙂
Picked off the ribs in the usual order, but instead of sanding or scratching with a knife, I used a damp cloth and a small iron.
Pressed the hot iron with his right hand on the glue wires and the remnants of the ribs and pulled in the damp cloth with the left. The heat, moisture and friction were a good combination. The adhesive blades disappeared and the remnants of the ribs could easily be scraped and dried off. No loss of fiber!
This will be my standard method for cleaning up the inside.