Here we go again... Dry shampoo isn't meant for super dirty, greasy, sweaty hair. It's a product to be used between washes or to add texture if you've just washed your hair and need some volume. That's it. If I wash my hair in the morning, I'll add it to my roots right before bed. Then, when I wake up in the morning, my hair is ready to go and I'll wash it the next day. Or, if I wash my hair in the morning and want to wear it up in the evening, I'll use dry shampoo to texturize it. It's really not rocket science. Read the back of the can ffs. This stupid "concept" of dry shampoo was totally invented by you.