Rent a carpet cleaning machine and the product they sell with it. It is cost effective and easy. Read the other answer about this question that was posted in the last 36 hours.

It depends where you are. I rented a big yellow steam cleaner last year for £35. It was really easy and really effective once you get used to using it. I cleaned the cream carpets in a 3 floored rented house of 6 people so we got our deposit back, worked perfectly!

Just search for your nearest machine rental place on Google. It’s not so expensive, these things cost £500, so to rent one for £35 is great.

Make sure you check if anybody you know can get you one, I didn’t realise but they had the exact same machine at work and they lent it to me for free later the next time I needed one.