I agree. It is the older cat that is spraying. Before I had my son, I rescued abused cats. I ended up with five at one point. When we moved, the cats got upset and pee'd on all of our boxes of household items, including clothes. The oldest (21 yrs old) recently pee'd on a bag of clothes I received from my aunt. Grrrr.
Anyhow, here are some things I recommend. First, get a black light (Amazon has good prices) so you can target all the areas the cat pee'd . If you don't the cat WILL return to do it again.
Here is a sure fire recipe for removing cat urine odor from carpet. These items are things most people have in their house already.
Ingredients
Baking Soda
White Vinegar
Dishwashing Detergent
3 % Hydrogen Peroxide
1. If the cat urine has dried and you are not sure where the soiled area use a black light to detect it. In a darkened room the black light will pick up urine and other stains. Hand held black lights can be purchased for between $15 to $25 on Amazon.
2. Next, wet the area with a solution of 50% white vinegar and 50% water. Make sure you use enough of the solution to penetrate the fibers deep down. Allow it to almost dry. You can assist drying by blotting with paper towels as described above. If you own a wet and dry vacuum extractor use that to remove excess moisture.
The acidity of the vinegar will neutralize the ammonia in the cat urine.
3. Apply a liberal amount of baking soda over the affected area and drizzle it with a quarter of a cup of hydrogen peroxide mixed with a teaspoon of liquid dishwashing detergent. (not caustic detergent that you put in a dishwasher) Work it in with a scrubbing brush or your fingers (be sure to wear rubber gloves) to dissolve the baking soda and work it down into the carpet. Allow it to dry. Then vacuum.
Important little tid-bit. Check house hold cleaners for ammonia. Never use ammonia or ammonia-based products on the carpet. One of the ingredients of urine is ammonia and your cat may well be encouraged to re-offend in the same area if it detects the smell of ammonia.
FOR CLOTHES and LAUNDRY. Use this method on your clothing, bedding, rugs or anything you think you can stuff in the washer (not including your cat). Simply add ¼ cup apple cider vinegar along with your normal laundry detergent, start the washer and VOILA!