I just did an interior today with a very dirty,smoke filled headliner. I simply used Folex(from Lowes). Sprayed a little on the headliner and then rubbed back and forth with a terry towel. Everything came out very easy. Headliners arent as hard to get stuff out of. My experience anyway. Be careful not to drench the headliner because too much product can make the adhesive week and later the HL will start to sag.