Try Flash wet wipes - SWMBO had a go at my headlinings with some this afternoon and they worked really well, but it must depend on all sorts of variables. That was on the fair face - removing it from the backing, latex grip gloves work quite well.
Er yes i happen to have had to do this, of course due to previous owners over enthusiasm with contact glue.
I used cellulose thinners, same as acetone (nail varnish remover.....) happen to have stock for spraying body on GRP lotus elan..... My headlining is a moulded GRP so it was fine on that, if the lining is anything else be very cautious!
well opened hatches and good breeze recommended for several hours after.