Like one of the ingredients in the hair product has water. Also can i use oil and grease for my hair
Hard dry fast: no water, no shower, no washing ur teeth, no washing hand. Basically no contact at all with water, if u want it rly hard try staying in a non-humid environment.
Edit: the concept behind that is that your skin becomes a sponge if you water is not available therefore your pores get larger and start absorbing water from everything they can, water on skin, humidity etc