Summarize the following:
If you don't have a hose at home, go to a local carwash and use theirs. Spray down the surface of all your tires. If you notice any tough dirt spots, move the hose closer to the tire so the stream of water is more powerful. Use a store-bought cleaner designed specifically for rubber tires. You can make your own using water, a few drops of dish soap, and a spray bottle. Spray all over the surface of your tires so they're completely covered with the cleaning mixture. Don't worry if you get some cleaner on the rims. If you don't have a spray bottle, mix your cleaning solution in a bucket and apply it with a rag. Bring the brush back and forth over surface of the tires. Press firmly over any dirt or grime patches so they come off. If the bristles of the brush accumulate a lot of dirt, rinse the brush off. Microfiber towels are better at picking up particles than regular towels, but you can use a regular towel if that's all you have. Wipe the towel over the whole surface of your tires to remove any leftover cleaner and pick up lingering dirt and grime. When you're finished, your tires should be nearly dry.

Summary:
Rinse off caked-on dirt on your tires using a hose. Spray the surface of your tires with a cleaner. Use a hard-bristled scrub brush to brush the cleaner into your tires. Wipe down your tires with a dry microfiber towel.