Here's why:
* Enzymes: While biological washing liquids contain enzymes that break down organic stains, they are primarily designed for food and bodily fluid stains on clothes, not the complex protein structures found in urine.
* Deep penetration: Dried urine has a tendency to penetrate deep into fabric fibers. Even with strong detergents, it's difficult to reach and neutralize these deep-set stains.
* Odor: Cat urine often carries a strong ammonia-like odor. While washing liquid might remove some of the surface odor, it's unlikely to eliminate the deep-seated odor molecules.
Alternatives for removing dried cat urine:
* Enzymatic cleaners: These cleaners specifically target urine enzymes and can break down the protein structures that cause stains and odors.
* Vinegar: White vinegar can neutralize ammonia and loosen urine stains, but it might not completely remove the odor.
* Baking soda: Baking soda absorbs odors and can help to neutralize urine, but it might not be effective on deep-seated stains.
Important note: Always test any cleaner on an inconspicuous area of the fabric before applying it to the entire stain.
For stubborn stains, professional cleaning services might be necessary.