How do you clean the grime off car upholstery

https://shop.advanceautoparts.com/r/car-projects/how-to-clean-your-cars-upholstery

have you thought about renting a carpet cleaner?

Otherwise, Dollar store Awesome rug cleaner and lots of toweling or old clean T-shirt’s. Bissel also makes a great foam rug cleaner. Rather than a regular vacuum, use your shop vac. It’s got better suction.

Fabric or leather? Here are some great sites with step by step guides!

https://m.wikihow.com/Clean-Car-Upholstery

https://www.best-auto-detailing-tips.com/how-to-clean-car-upholstery.html

https://www.cleanipedia.com/me-en/car-vehicle/clean-car-upholstery

I use the upholstry tool on my carpet cleaner..... I recently ran into our local car detailer in the Dollar Tree, and he had an arm load of Awesome Degreaser.... I said boy he most have a cleaning job, he said this is all he uses on cars including the interior.... so try it. It is one of my favorite cleaners for my clients, it will cut through anything. You can put it in hot water in your carpet cleaner reservoir too. I wear rubber gloves as its a bit hard on the hands. Otherwise I would get a real soft carpet brush and dip it.

Pay to have it detailed.

There are ready made cleaners available at your local automotive supply store. There is one which is a spray foam and has the plastic brush type cap. This works very well. I use it on the floor mats too.

Mr Clean diluted in water and microfiber cloth, scrub, rinse repeat, change out water when it gets dirty