Normal carpet cleaning chemicals work pretty well on everything except red stains and iron stains (rust from the metal feet of a chair or table that was placed on moist carpet would be a common source of rust stains)
Red stains are of two types :
– Organics like fruit juices, red wine (probably most common) and tomatoes
– Non – organics like red dyes (including dyes added to apple juice to mike it look like a more expensive juice ) and medicines.
A ) Get a specialized red dye spotter targeted for whichever type of stain. janitorial supply distributors, many carpet stores, possibly Home Depot or Menards, and many better hardware stores will stock these.
B) Follow label instructions.
C) I’m told that the old “steam iron and a clean white cotton cloth” means of wicking the dye out of the carpet is no longer absolutely necessary – but that it still helps a lot. Any application of heat will speed up the action of most carpet cleaning chemicals, and the instructions may suggest a variety of ways to apply heat.