Ian
I did my Carpet Inspectors training with Woolsafe. The tutor was Dr Eric Brown.
After I qualified there were no local areas available to me, the closest being south of Oxford. So I decided to be independent and offer my services to local contacts only.
If you visit woolsafe.org you'll see a little about the Woolsafe Carpet Inspectors programme. Even if you don't do inspection work, the course is beneficial to us as cleaners. I don't know if the training courses are still running, if not, why not approach Eric directly and see if he's running any more in the future. Maybe if there was enough interest from other CCer's..............
James123
Whilst I agree that over application of many retail products cause us problems, these retail products tend to have a lightening effect on the surrounding carpet and very rarely blackening. However, other home products such as washing up liquid and other stickily residual household formulations can promote resoiling and leave the soiling you mention.
I have stated this before, it's worth repeating and I know there'll be a barage of abuse, but the reality is the truth. I have on many occasions been requested by the UK carpet manufacturing industry to demonstrate on their behalf at consumer shows how best to care for carpets. I demonstrate correct vacuuming and correct spot removal techniques. I ALWAYS use generally available branded spotters, typically 1001 Trouble Shooter (Woolsafe Approved) and I've NEVER had any problems. I treat spilt tea and coffee on a woolblend beige twist. My tools are a terry towel, paper towel, a teaspoon, 1001 and a bottle of water. The problem is NOT the product, but always the user, typically applying far too much product and rubbing/scrubbing too hard. Basically, they panic
SAFE and happy cleaning
Ken