Oxidation for Cleaning Urine in Wool and Silk
Oxidation works best on proteins. Urine can contain protein but the real cleaning problem is urine salt crystals. It is the off gassing from the urine crystals that stink. With enough work, flow, and time water will dissolve urine salt crystals. But acid does it faster and better. Wool in its natural state is slightly acidic and urine salt is alkaline. Dyes can be destabilized by alkalinity and acid helps to reverse that damage. So you can use a vegetal acid such as vinegar or in its stronger form glacial acetic acid or you can use a more stable and longer lasting mineral acid. Urine pretreatments use mineral acid as their main ingredient.
The other consideration is that oxidizers work best on proteins but wool and silk are protein based fibers. All oxidizers are long term bad for wool and silk. In moderation the damage is minimal. But the best advice that I know is that oxidizers should be used only on wool and silk when there is no other remedy and when they are used should be in low concentration. About the only oxidizer I normally use is 3% Peroxide for blood and protein stains. I would rather apply it a few times then over use an oxidizer once. If I had to clean a crime scene Oriental Rug soaked in blood I would likely go to one of the other oxidizers mentioned. But I never got one and doubt I will.