Showem, what is the stain on? You can't use Vanish on silk or leather for example. If I have a relatively fresh stain then a soak with some Vanish then a hottish wash with some Vanish added to the wash cycle works. If the stain is on my white sofa covers (which aren't as unpractical as you might think) then I bung in some Ace or Sil bleach with the Vanish (but make sure that the room is well ventilated) and wash as hot as possible.
Do NOT use salt - this will fix the stain (so sez the Good Housekeeping Institute) and white wine only works on carpets.
Willy's method will probably work too.
The vast majority of washing powders use enzymes to get things clean.
The ones that don't are called "non-bio" or (in Germany) "sensitive", so brands like Fairy Snow or [img]http://www.persil.de/images/sensitivegel.jpg[/img]
Here is the technical bit:
The enzyme may be a protease to break down protein stains or a lipase to break down fats and oils (lipids). The breakdown of protein and fat molecules is called hydrolysis which simply means reaction with water. The enzymes catalyse these hydrolysis reactions and so help with the removal of stains. Biological washing powders are used at a low temperature because a higher temperature might prevent the enzymes assisting in the cleaning process. Non-biological washing powders are used at a higher temperature because this increases the rate of the cleaning process (i.e. they have no enzymes but lots of soap in).
My best friend at Uni was/is a chemical engineer so it sort of rubbed off

Katrina