Just as a note for anyone considering soft top cleaning as it seems to come up a lot of late, the zed had been a little neglected recently (I'm building it a driveway in coming months ffs)... so the roof had the notorious green tinge coming in where it meets the seals along the back edge of the boot.
Anyway, for a standard fabric roof, the Autoglym roof cleaner and supplied weird sponge is bloody superb. Can be bought from halfords too.
You can get a stunning finish without the sealer, all I did was:
Mist coat of water over roof
Small jug of fairly hot water
Spray cleaner all over roof (about 6 inches between sprays)
Wet sponge in hot water and squeeze out thoroughly
Go hell for leather in straight lines in one direction until sponge is visibly dirty (it's white), rinse, squeeze, repeat.
Finish the roof
Replace water, apply more cleaner.
Go hell for leather in other direction in straight lines
Replace water, apply more cleaner.
Go hell for leather in circles.
Open hose to rinse off thoroughly.
This should cover all eventualities with regards to "opening the pores" of a tri layer fabric roof (which many BMW's/Audi's are now) and really doesn't take very long.
It can then be sealed, but only if you have a garage really.
I also have a bird poop burn on my bootlid, and it feels very contaminated. I need the units
@Scrooge 's cabinet of goodies.