Do you have a dog or cat that has occasional accidents? As a life long pet owner (and current mom to 4 dogs) I know the importance of getting the stain up as soon as possible a long with the smell so the dog (or cat) won’t continue to use that spot as their personal toilet.
There are some great pet stain removers on the market available at your local pet store but they can be pricey. I have a cheap, simple and eco-friendly solution.
First, using a paper towel, soak up as much of the stain as possible (see puppy training tip below). Now, just saturate the area with a little white vinegar and let it set a few minutes. Then using a sponge, soak up as much of the liquid as possible, wring the sponge out and keep doing this until the spot is only damp. Then I wipe it up some more with a dry dish towel or even better, a microfiber cloth and fluff the carpet fibers back up.
If the stain in question is caused by a puppy in the process of housetraining, take the paper towel with the dog waste on it and take it outside to where you want the puppy to actually do his business. Then take your puppy out there to that spot. The puppy will smell it and associate it to where he should “go potty”. I learned this trick when I worked at PetSmart from the dog trainers.