I would say a fly sheet or blanket helps to protect them from the dirt
For spot cleaning(or cleaning of green stains or pee stains) you can take rubbing alcohol in a spray bottle and spray it on the spots and rub with a rag. Works great, especially at shows if you need a quick clean!
Daily grooming with lots and lots of currying. It helps get dirt to the surface of the coat and with lots of it, it really makes the horse shine. I don't recommend bathing with shampoos all the time because it strips the natural oils in the horses coat and then they won't have that nice and bright shine. If you have a product called Show-Sheen, you can spray it on your horse before they go outside. It makes the coat slippery (so don't spray over the saddle area) and will make dirt and grime harder to stick to the horses coat. Daily stall picking helps keep manure stains under control also. Hope this works!
I use miracle groom but it is a little hard to get some out and it works pretty well then and has an amazing smell
Yea I ride a Grey horse and she probably is the one who the loves to roll most. I think that cowboy magic shampoo and cold water works for me. It gets her so clean and bright. I don't know if the cold water helps but sometimes I use warmer water and it doesn't work as well. I usually bath her every two weeks
I don't think it's possible 😂😂. The grey horse I ride gets a bath weekly, so she never gets super dirty. I guess if you don't want to bathe often, maybe use green spot remover or rubbing alcohol every time you see a stain. I would just remember that it's a horse, so it's never going to stay or be truly clean.