Ewwww! Yup... that's what happens to cups when you drink a LOT of tea and they're only handwashable. But, do not despair, there's baking soda!
So what exactly am I rambling about? Well, I have a lot of coffee/tea mugs that are not dishwasher safe. No biggie- I just wash them by hand... but the stains don't always come off by a simple sponge and soap. Now when I found out about baking soda as a stain remover, the above mug {and a few others} had about 2-3 years of stains on them! So take the above staining at the bottom of the mug, and imagine the entire mug stained like that. Ewww! I know....
Enter the baking soda!! Just sprinkle a little in the bottom of stained coffee mugs {or most any normal dish... double check about special surfaces though}, put in enough baking soda to make a bit of a paste, scrub it around the cup, and voila!
Presto, chango, clean cup-o! Yup, baking soda instantly washed away years of stain build up! {OK, so maybe not "instantly" as it did require a few minutes of scrubbing!} Again, if you have special surfaces, double check that baking soda won't do them any harm before you sprinkle away. As far as I know, most surfaces should be fine, and I use it on all of my dishes that need a little extra scrubbing power :)