If it's warm and you're struggling to keep the socks clean try stockings for women. Just cut off the feet part and slip them on to your horse, it's great cause it can go higher up that some boots. I do recommend that you just check if your horse is ok with the idea.
Spraying a show sheen can help prevent stable stains too! And we normally put the tail inside one leg of a pair of tights and then use a tail bandage to keep it on! Stops her from getting any poo in her tail!