Hang ten or Spirit of 76?...

As far as cleaning automotive fabric upholstery.

There is a solution that I use that works quite well.

It's a mixture of 10% vinegar, 20% club soda, a few drops of Dawn Dish soap to help cut the grease, and the remainder Distilled Water in a gallon container.

Vacuum seats good first and blow them down with high pressure air to get the loose dirt out of the fabric.

Next put your mixture in a Spritzer Bottle and start wetting down the surfaces, giving it some time between sprays to allow it to seep into the fabric surface. Can help it along with a clean terry cloth towel in circular motions. Keep the surface wet for a good 1/2 hour, being careful not to soak it so much that it goes down into the foam.

Keeping it wet for some time allows the vinegar to start breaking the dirt and stains down. As it starts to break down, the club soda is bubbling to bring the dirt up to the surface and you can pick it up off with a clean terry cloth towel.

Repeat until you feel satisfied that it is coming clean. Dry down as best you can with the clean terry cloth towel then take a Spritzer bottle with Distilled water to it for the final rinses, drying with terry cloth towel. Vacuming moisture out, and final blow down with compressed air.

Don't be in a hurry, give the chemicals time to work and release the contaminations.

Let dry, I am sure they are going to look a lot better for you.