Wool carpets provide natural stain resistance, so spills often don't penetrate too deeply into the fibres. However, tea stains and spills can penetrate more deeply into the carpet fibres if they aren't cleaned up immediately. Wool is also prone to shrinkage, so carpet shampooers cause more damage than they remove. Many commercial stain removers contain bleach, which dissolves wool fibres on contact. Detergents sold for use on wool clothing clean wool carpets without causing damage to the fibres.
Lay a clean, white cloth or towel over a fresh tea stain. Press on the cloth, blotting up the liquid. Remove the cloth as it becomes moist from the soaked up tea and replace it with a dry cloth. Continue pressing and blotting until most of the liquid is absorbed out of the carpet.
Mix 1 capful of wool detergent with 1 to 2 cups of lukewarm water. Soak a white cloth in the solution.
Dab the solution onto the tea stain. Avoid rubbing, which may spread the stain. Continue dabbing until most of the stain is removed.
Soak a clean cloth in clear water. Blot this onto the cleaned area, removing the wool detergent from the carpet fibres.
Lay a dry towel over the cleaned carpet and set a weight on top, such as a stack of phonebooks. Leave the weight in place overnight or until all the moisture is absorbed from the carpet and into the towel.
Avoid acidic cleaners, like ammonia and vinegar. Acids damage wool and may discolour the fibres.