Some stains will never come out, and it is possible to ruin the garment trying. General principles of stain removal:
- Time is not your friend. Wash the garment as soon as possible.
- Scrubbing excessively may leave a damaged spot on the garment.
- Many garments are not color/chemical safe, and many chemicals will damage certain fabrics.
- Fur, leather and suede must always be taken to a dry cleaner who specializes in leather or fur care.
- Hot water can set (“cook in”) protein stains (food, blood, grass, mud, feces, etc.), so wash in cold first. Hot water is needed for other types of stains (like tannin stains – wine, berries, coffee, tea, tomato juice – and oily stains).
For more details, check out this awesome article from the Cooperative Extension Office of the University of Kentucky. You can become an expert!