How are headliners cleaned?
Very carefully. Most headliners are made of fabric glued over foam, cardboard or plastic. Too much scrubbing or too much cleaning liquid can ruin the glue and cause the fabric to droop. The same goes for certain fabrics glued onto door panels. The best way to clean a headliner is with a steam cleaner and gentle rubbing. If a headliner is in questionable shape, you may want to avoid cleaning it to prevent the fabric from peeling and drooping. If you are lucky enough to have a plastic or vinyl headliner (found in cheaper cars, some imports, and older cars) they are easier to clean and are more durable. Droopy fabric headliners are hard to fix-you need a can of spray glue and lots of patience to fix them.