Lay the couch on its back to expose the metal bars, taking care not to gouge the hardwood floor.
Using a lint-free cotton cloth that has been saturated with rubbing alcohol, clean the metal bars by rubbing vigorously to remove any dirt, grit and oily residues. Allow to air-dry for five minutes.
Apply an adhesive-backed felt strip to the first metal bar by peeling off the protective paper that covers the adhesive, and then aligning the felt strip along the length of the metal bar. Press firmly into place by applying hand pressure the length of the strip.
Repeat the process with each metal bar, then return the couch to its upright position.