Clean Your Collars
It's only natural to want to wear your favorite shirts as often as possible. And even the cleanest men can be afflicted with ring around the collar and dingy cuffs. That stain you see embedded into your favorite shirts, sweaters and jackets isn't really dirt—it's actually a build-up of sweat along with the natural oils from your skin (and maybe a touch of cologne or hair product). That's why standard washing rarely removes it.
Removing the Grime
Run the collar under warm water and add a dime-sized amount of shampoo or dish detergent (like Palmolive) to the center of the stain.
Take the fabric and rub it against itself, working from the center out to the ends of the collar.
Lather, rinse and repeat if necessary
Toss the shirt in the regular laundry and it should come out good as new.
Prevent future rings by washing your light colored shirts after every wearing. Run a gel stain remover, like Shout Advanced Ultra Gel ($4) before washing.