It will depend upon what the stains are, but CLR is probably the best first choice, especially for "hard water" type stains. It is an acid, albeit fairly mild; so any finish on the terracotta, anything to make it shiny, might need re-application.
use Angel Eyes. http://www.angelseyesonline.com/ amazing product. it really works. they got rid of my Bichon Frise's tear stains. you should try it out.
You get rid of oil stains by using oxce clean
To get rid of stains on a white jacket, first identify the type of stain and pretreat it with a stain remover. Wash the jacket in warm water with a bleach alternative or whitening agent, then air dry or tumble dry on low heat. Repeat the process if the stain persists.
Cosmetics stains are very hard to remove. I had a bottle of concealer spill on my bathroom floor and I was never able to have it removed. You can try scrubbing the area with baking soda, baking soda is great for everything.
your mom
peroxyed
you cant do anything to get rid of your second floor.
Rub it clean with arsenic
Try Resolve carpet cleaner, that worked to get most all of the stains out of my carpet when i moved.
Try a little bit of Golden Syrup (see 'How do you remove grass stains?)
Clorox is a company that has detergents that helps whiten your whites (helps keep your white clothes white) and brightens your brights (gets rid of stains in your colored clothes and keeps it looking new).
You can remove hard water stains from glass vases by soaking them in a solution of equal parts white vinegar and water for a few hours. Scrub the stains with a brush or sponge, then rinse the vase thoroughly with clean water. Alternatively, you can use a commercial glass cleaner that is specifically formulated to remove hard water stains.