if dirt/blood had influence on intimidation / charisma checks then it might be something worth having implemented so early in EA, before the vast majority of the game is completed. This is flavour that should have been ignored until later on.
Short rest should clean yourself up but, no need for more junk items like hankies, and it should take alot longer to get dirty. Clean in the morning, 10 minutes later covered with filth. Just a pointless and unnecessary addition that brings suggestions like this to distract you from finishing the game.