If your bike helmet is getting greasy and dirty, this is a quick, easy way to clean it with hardly any effort!
Hair (Sorry if you're bald. You'll have to improvise.)
When you get to the shampoo step, lather up.
Then simply plop your helmet on your head while it's still loaded with shampoo.
Move the helmet around a bit and scrub the straps with your hands.
Rinse it while it is still on your head, and take it off and rinse it a little bit more.
If your helmet was really gnarly, you might want to wash your hair a second time without the helmet....
Dry it with your towel, then set it out in the sun for a couple of hours -- bottom up -- to complete drying before you use it again.
That's it! Pretty dang easy, huh.