Ink stains spread rapidly. Often the first error in treating a red ink stain is to use a solvent first. This will cause the stain to spread. The key to removing a red ink stain and not making it worse is to use something to contain it. If the carpet doesn't consist of natural fibers, surround the ink stain with a barrier like water or a mixture of hydrogen peroxide and few drops of ammonia. If your carpet does consist of natural fibers, such as wool or cotton, use only the peroxide or water to try to contain the ink. Ammonia may damage these natural materials. Creating a perimeter around the stain prevents it from setting into the fibers if it spreads. Once the stain is contained, you can move on to removing the stain.
Ammonia is non-bleaching, which means it will not discolor most carpets. It is also highly alkaline and can remove red ink stains from carpeting if used correctly. Mix 1/4 cup ammonia with about 2 qt. warm water and blot the solution on the stain. Dry with a towel and repeat. This may take several applications. Rinse the area thoroughly with clean water when the stain is gone.
Although red ink is one of the most difficult stains to remove, using hairspray while the stain is new may be an effective remedy, particularly on natural fibers that other products may damage. Spray the stain, but be careful not to overspray. If you apply hairspray to the area around the ink, or saturate it, the stain may spread. Blot the stain with paper towel and repeat. Do not rub. Rinse the area with clear water and dry the carpet.
If you have rubbing alcohol in your medicine cabinet, you may be able to remove red ink from your carpet. Ninety-percent isopropyl alcohol typically works best but 70-percent may also remove the ink. Blot the stain with a cotton cloth dipped in the rubbing alcohol. Do not pour the alcohol on the stain and do not rub it in or it will spread. Use a dry cloth or a shop-vac to absorb the alcohol and repeat until the stain is gone or until no more color absorbs into the cloth. Rinse the area thoroughly with water.