General purpose cleaner. G101 or similar. Have a look for general interior brushes. You don't want the bristles to be too hard though it may drag the lining away. Don't use too much water either if its the original headlining as the glue may separate. Put it in a spray bottle if you can, and give each area a lights spray as you go. Work in sections too. Don't worry too much, I was worried but it came out really really well without too much effort!
