Summarize this article:

Hold the top of 1 boot in each hand. Knock the boots together several times so that the heels collide. Any large pieces of debris or mud will fall to the ground.  It’s essential to do this outside to avoid making a large mess inside your home. This will save you a lot of time during the cleaning process because there will be less mud to remove. Measure out 1 L (0.26 US gal) of warm water in the spray bottle. Add 4.9 mL (1 tsp) of dish soap into the spray bottle with the warm water. Close the bottle and shake it well to make the mixture bubble. Place the boots into either a utility sink or a large plastic container. Spray the full exterior of the boots, including the soles. Be careful not to spray the mixture inside the boots. If you clean your boots in a plastic container, you can simply pour the mud and water outside when you are done. After 3 minutes, use a rag to wipe the soap and dirt away. Start at the top of the boots and work your way down towards the soles.  Rinse out the cloth with water if it gets too dirty. If your boots have zippers, use the rag to gently brush down the zippers. This will remove any stuck dirt. If there is still dirt left on the soles of the boots, add more water and scrub it away using a brush. In most cases, however, using a rag with warm soapy water will be enough to clean the soles. Take a clean rag and gently wipe the soapy water off the boots. Then place the boots upright in the shade to finish drying.  You cannot dry Hunter boots in a dryer. Avoid drying or storing your Hunter boots directly in the sun. This is because the heat can damage the rubber which will shorten its lifespan. Gently rub a clean pencil eraser over any scuff marks on the exterior of the boots. Use the same motion that you would to remove pencil markings. Wipe the boots with a clean rag to remove the eraser debris.

Summary:
Take the boots outside and knock them together to remove excess dirt. Mix warm water with dish soap in a spray bottle. Spray the boots with the dish soap mixture and let it sit for 3 minutes. Use a clean rag to wipe the dirt off the boots. Scrub the soles of the boots with a scrubbing brush if necessary. Wipe the boots with a clean rag and then let them air-dry. Rub an eraser on any scuff marks to remove them.