My interior needed a clean as my seats were filthy with loads of water marks.. heres how I cleaned them:
First vacuum the seats and carpets thoroughly
Then have two buckets - one of cold water and the other of hot water with normal clothes washing powder in it
dip the plastic brush (like this one: http://www.chinatraderonline.com/Fil...2253961282.jpg) into the washing powder water and apply to the seats roughly. Then scrub the seats hard with the brush and continue to do so until the seats look clean and is evenly wet.
Then get a towel and dip into the clean cold water and rub the seats with this , trying to remove the soapy water and dirt.
Do this process twice (spray abit of vanish then scrub for stubborn stains) and then do the carpets too.
Leave to dry.
My seats look spotless! No need to buy espensive interior shampoos etc. Washing powder and vanish is perfect.
Good as new now!