All you need to make your car tires look new again is warm water, dishwashing soap, a bristled brush and some tire protectant. Mix some dishwashing liquid in a bucket of warm water and use a bristle brush to scrub the tire clean and rinse off the soap. Don’t use a steel brush or one that is too hard, you could damage your tire that way. If there is still stuck grime on the tire leave the soap mixture on the tire for a few minutes to soften the dirt, then scrub again and rinse. Repeat if necessary.
Depending where you live you can seek out a good tire protectant to apply making your tires look polished and shiny again. 303 High Gloss Tyre Shine is a good example and these products repel road grime and will make your car tires look new again for much longer.