How can the engine and ducts of a 2001 Toyota Corolla be cleaned after a mice invasion without using chemicals?
After restoring a good number of vintage cars as well as vintage electronic radios, cleaning the nest material is, as commented done with a good strong vacuum.
But it is the feces and urine that is the issue and concern. These present both damaging effects on car materials and health risks to humans. The urine is acidic and will etch and eat metals and materials. Bacteria and virus exist in both. Mice viruses
So at minimum vacuum out the nests wear a face mask protect both eyes (tear ducts) and inhalation. Then at minimum use a disinfectant (lysol, clorox).