Find out the source then you can select the proper chemical. Cat pee in a hot car will curl your nose hairs, smells like dead fish. The only way to get that out was remove the carpeting. We sold the car
You can rent an Ozonator from a rental shop that will permanently kill the odor. These are very powerful and can even get rid of the stench of rotting flesh or smoke damage from a building.
We had someone come out and use one on a used TT we once had. Cost us $150 and worked great.
Scott, Grace and Wesly
2003 Dodge 3500 4x4, 6 speed Cummins (lightly bombed),
2004 Forest River 25RKS many, many mods.
H0NDA eu2000i