Sorry I just want to let you no who ever told you that can't be removed it can the main issue you have is with age and the traffic built up on the carpet I'd recommend using nothing but a hand tool present spray with a standard washing powder detergent and brush in using a hand brush do it 2 or three times before cleaning go over it and then after get a citrus carpet cleaner gel it will help the excess and bring up the carpet allot better .. Personally Its not a easy job but asking as you take your time with it ... It will come out allot better!!!
Well done! Now I understand why my floors are still dirty after they were professionally cleaned 3 years ago.
Sorry I just want to let you no who ever told you that can't be removed it can the main issue you have is with age and the traffic built up on the carpet I'd recommend using nothing but a hand tool present spray with a standard washing powder detergent and brush in using a hand brush do it 2 or three times before cleaning go over it and then after get a citrus carpet cleaner gel it will help the excess and bring up the carpet allot better ..
Personally Its not a easy job but asking as you take your time with it ... It will come out allot better!!!