When I have a proper soak in the bath - I find that scraping a fingernail on the skin of my neck tends to result in a lot of what can only be described as dirt under the nail - this obviously comes from riding the bike and is worse if it’s been raining because the dirt gets sprayed onto you. My shirt collars get filthy as a result of this (and i don’t even wear them on the bike!)
I reckon us bikers must have some of the dirtiest necks in the country?
Be prepared for a shock mate - I like to think that I am a clean person who showers every day (my neck on the avatar looks nice and clean) - but the dirt can get really ingrained around your neck which is exposed to the air. The dirt tends to scrape of most easily after a fairly good soak in a hot bath.
Also treble up as a balaclava if it right perishin’ guvnor. Took mine off after a hoon around the countryside in the hot weather and found a dead wasp and a dead bee that otherwise would have been sticking out of my neck.
I had a Buff a few years ago, very useful. Think I got it in Snow+Rock. Makes a great pirate’s bandanna too, used to wear it like that at work and people thought I was barking HAH!