There were these mystery stains on the face of the collars on my two favorite blue dress shirts. Stains on the part of the collar touching my neck made sense--all that nasty skin oil day in and day out. But there were these white deposits on a part of the collar that never touched my neck.
I went to my dry cleaners and asked them to work on it, what with their strange, powerful, loud steam-cleaning implements. They were not optimistic, and their not-optimism proved founded. (N.B. My dry cleaners are comically bad at times, but they're very sweet and extremely convenient.) Rather than Goodwill the shirts after far too few wearings, I thought I would try the Spray-n-Wash stain stick which I keep in the laundry closet. I put a generous helping on the collars, threw the shirts in the wash, and Hey Presto! see above. The stains are gone.
$0.10 worth of a $5 laundry product available at the grocery store rescued $80 in shirtings from certain loss. And thus did it earn the honor of being designated a Secret Weapon.