I'm not sure how it works or why it works but it does. Magically.  The moment you get a berry stain (strawberry, blueberry, tomato, etc), fill your kettle with water, boil it, then stretch the fabric over a large bowl (get it as taught as possible over the bowl so the fibres are pulled apart) then pour a slow steady stream of boiling water into the fabric stain.  For some reaon holding the kettle about 18 inchces above the fabric seems to work best (perhaps the force of the water coming down adds an extra boost.) 

You might have to do it several times.  If the stain's still not 100% out, try rubbing a tiny bit of soap on the spot and then pouring the water (careful, if its a color that might fade with soap and hot water.)  

The key to this natural method of stain removal is speed of action -- ie. if you wait an hour after the stains settled, your favorite shirt may become a dish rag.