I cleaned the roof lining over the weekend, it was filthy! I used a can of CIF bathroom mousse (yes really - tip taken from the FTOOC forum) and a couple of towels, pretty simple technique, but it worked wonders:
1. Apply plenty of mousse to a small towel and work it into a section (1ft²) of lining, use a bit of force to scrub in.
2. Using a damp towel, go over the section once more and then soak it all up by scrubbing with a dry towel.
3. Repeat the above on remaining roof sections.
And thats it. Took about half an hour and the results were impressive, I was sceptical about the CIF idea but it really did shift the dirt with ease.
CJ