For my carpet mate...(FRST).....bit extreme i know, i took the whole carpet out and Karchered it using carpet cleaner and jet washed with a turbo lance, then hung it up on a wall to drip dry...PERFECT AS NEW!!!

Ive also done this previously to another FRST, grey carpet, which had been sitting in a breakers for a number of years, and was 4 inch thick in leaves, mud and shite.....This came up AS NEW!!!

As mentioned, i am anal, but if you dont fancy Putting the Karcher on it then a 3-in-1, carpet cleaner together with a machine vac might suffice??? Depends on how stubborn the dirt etc!!

Hope this is of help??