I have found a great way to deal with stains on carpets. I have seen this on the web, and it looked like a fake, so I just laughed at first. But then I got a stain from coffee on my carpet, and remembered this routine. Here I will tell you how the cleaning went, and how it was described.
So usually, I take a bit of white vinegar and just moisten the stain with it, then I blot with a damp cloth until the stains is gone, dry with a towel and leave to dry completely. The routine I saw on the web was much more different. I've never seen until then someone using a window cleaner for removing stains on carpet. But hey, it was worth a shot, since I've just cleaned my windows yesterday, and I had about half a bottle of window cleaner left.
I must say that no end of tenancy cleaning in Canary Wharf area, my area, have never even considered this. Mostly it's because many carpets are much more delicate and you may damage them this way. But mine was quite and old rag, which I didn't care much about, but sill a view of the stain was pretty nasty, so I had no worries about it.
First, you sprinkle some window cleaner onto the stain. Make sure that you cover it all up. Then, you use a scrape of an old rag, as a scrubber. Usually Tooting end of tenancy cleaning teams would suggest to blot the stain on a carpet, not rub it. Sounds, logical, you don't want to spread the stain all over the place, and more likely keep it contained. Here though, you rub the stain straightforward. Take a piece of scrap carpet and rub the stain. It goes away within seconds. You do need to put some force into it, but it works.
Which is more, since you're scrubbing with a piece of carpet, you don't harm the fibres, or at least not that much. Just make sure, one – you don't spill too much window cleaner, since too much liquid on a carpet can damage it, and two – use the same coloured carpet scrap as your carpet, since if it's painted in a different colour you may get some discolouration.