I am assuming you are talking about material. The way that I clean my customers rag tops is start with a very soft plastic brush or boars hair. If you use a plastic brush its something like a finger nail brush (that soft) The product that you want to get online is Ragg Topp as suggested. They have a cleaner and protectant.
The process, working with on a cool surface, get the top wet and spray on the cleaner, let dwell for a minute to work in. Then with your brush gently work that into the surface. Since yours is tan there should be a dramatic difference in the cleaned areas. There is a lot of embed dirt in the material. finish up the top re-working areas as needed. Rinse real good and dry off with a good waffle weave micro towel. Once the top is completely dry I use my shop vac with a brush attachment, to lift any debris that are still in the material. One of my customers has a car that sleeps on the top. So the brush attachment lifts the loose hair that didn't wash out and anything else that is stuck in the material. Then spray on the protection. For good coverage I spray in one direction then go back over in the opposite direction.
Hope this helps....Is your back window plastic?