There are two home remedies for removing pet urine that I have run into over and over again on the internet. One is using vinegar and the other is using baking soda. I have seen suggestions to use these in different combination's with other additional products. I have also seen suggestions to use them without any products added. I am going to discuss Vinegar in this post and baking soda later. First if you are going to use vinegar make shore you use plain white vinegar. If you use vinegar with any coloring in it, you are just as likely to add a stain as you are of removing one. The coloring (dyes) in the vinegar can easily create a permanent stain.
Vinegar is an acid. Fresh urine is an acid base. When you try to remove an acid with an acid it is less than effective. Urine begins to change immediately upon leaving the body (human or mammal). This change involves, among other things, the creation of alkaline salt crystal (white powder like residue). These salt crystals are very alkaline (11+) on the Ph scale. After this has occurred then the acidic vinegar will help to neutralize that part of the urine residue which is now alkaline. The vinegar is a relatively weak acid and the salt crystal are a strong alkaline. You may need to use a stronger acidic spotter than vinegar for it to completely neutralize the salts. Once alkaline or acid is neutralized it can be removed easily. To remove it you can use absorption or extraction. Absorb it with a clean dry white absorbent towel or rag. Or extract it with a wet dry vacuum or similar piece of equipment. If you have a spotting machine that sprays a little cleaning solution on and extract it again this is best because you get a good rinsing action and you will remove more residue.
Vinegar as an odor remover acts as a masking agent. That is, the odor of the vinegar covers the odor of the urine or masks it until the odor of the vinegar wears off. Then the urine odor returns. Actually it has never left it has been covered from our ability to smell it by the vinegar.
Vinegar will act a rinsing agent like water to dilute the urine and if extracted or absorbed remove some of the residue.
Vinegar will act as a deodorizer by covering or masking the urine odor.
The acidic nature of vinegar will help to neutralize the urine alkaline salts in dried urine.
Cleaning acid with acid is not effective and can complicate your problem. By adding vinegar to the urine spot you will increase the volume of liquid and possibly soak the urine deeper into the carpet.
Vinegar does not digest, encapsulate, neutralize or change the odor molecules. It masks them.