Stains can increase interior detailing prices because they may require special cleaners, steam treatment

https://ricardogmcg079.talesignal.com/posts/how-detailing-resale-value-can-help-you-get-more-when-you-sell-your-car

Stains can increase interior detailing prices because they may require special cleaners, steam treatment, repeated extraction, or extra labor to improve the appearance.