Stain Solutions is a handy website developed by Susan Taylor at the University of Illinois Extension. The site is a database of dozens of common stains and the solutions to remove them. Click on a stain in the chart and you will be taken to a list of the ingredients needed to make a solution that will remove your chosen stain. Directions and warnings are provided along with the solutions.
Applications for Education
I don't know of any teacher who hasn't stained work clothes themselves or had them stained as the result of a student mishap. I've stained enough neckties to create a drop-cloth. Coffee, ink, and markers seem to be the leading causes of those stains. Solutions to remove all those stains can be found on Stain Solutions.
H/T to LifeHacker.