There's loads of good stuff in a sofa.
Leather, wood, rubber straps, stuffing even springs occasionally.
(Think bags, pouches, shock cords, handles, carving materials, insulation, padding and a myriad of small tools like awls and the like. The list is endless.)
Just break it all down, keep the best bits and then chuck the rest into the dustbin. Once you get your eye in you'll never throw such useful stuff out again.