All I can think of with this thread is:
"Must be a king."
"Why's that?"
"He hasn't got $#@$ all over him."
I like the dirt, blood and grime, but only when it makes sense. It adds some grit and immersion when my PCs have just fought hard against, say, the Gith. After a battle? Yes. After trekking through the bog? Yes. Jogging through the grove? No. Moonhaven streets? No. Maybe if you go through one of the dusty, old buildings or caves... Sure. But some good points have been made.
1. You shouldn't get filthy simply by jogging around talking to people or other light activities.
2. The filth should be easily cleaned off via short rest, splashing around in water, using an item like a towel, something.
3. I'm using this thread to once again push for more than 2 Short rests for the entire party because it would then allow you to frequently take breaks to short rest and clean off. Allow unlimited party SR for things like cleaning up and ability resets, but limit healing during SRs to 1 SR Healing per character level at the character level. Your MC is level 4? He/she gets 4 SR Healings per day. Gale is level 4? He also gets 4. You can SR as a party as much as you want and use SR Healing if you want on whatever characters actually need it. Either way, they clean up and regain special abilities and things like Warlock Spell slots.
It would be just another thing to encourage SR.