What are your most effective ways to get rid of old stains on carpets? I've already tried to clean it with a mop with lots of chemicals and with vinegar but there's no luck. Any tips or suggestions? I'd be grateful
Synthetic fibre or wool? Stain protection applied or not? Treated with hot or cold products? Lots of chemicals? Alkaline or acidic? Pets stains, food stains or body fluids? Detergents applied?
From the description you provide I'm guessing something which may have been a removable stain has been turned into a permanent one.