I have noticed stains (even when I just brown things) before that have disappeared after I do another dish, but I would prefer to get rid of them right away.
I use a plastic scrubber (no metal)and elbow grease, after soaking for a while in hot water. For really stubborn stains or burned on food, I add a tablespoon or two of chlorine bleach to the hot soaking water and let the pot sit for 15-20 minutes. Sometimes you can actually watch as the stains disappear in a few minutes. But a stain or two isn't so bad and is evidence of a well-used and much loved pot.
Oh, and be sure to rinse well after using bleach. I wouldn't use this in an aluminum pot, but for my Le Creuset dutch oven this method works beautifully.
You could also try some of the suggestions in these threads: http://food52.com/hotline... and http://food52.com/hotline...
I use a little Bar Keepers Friend in mine. It works great for getting those brown spots out.
barkeepers is great but careful using it on older enameled pieces - I ruined an old le creuset with barkeepers and over zealous scrubbing!
First, appearance matters less than functionality. You can try boiling some white vinegar in there but in the end I would say don't sweat it---who else but you looks at the inside of your pots?
Baking soda - make a paste and scrub.
i think the spots are how you show your love! a perfectly clean LC is one that's never been used. embrace the spots and call it "well seasoned".
P.S. mine are all a mess! and i love it!
I think Le Creuset has cleaning suggestions on their website, or used to.
Baking Soda,Baking Soda, Baking Soda!!
When I really screw up , And I do, lots, I cover the charred bottom with Baking Soda and then add H2O and boil it off while I wash the rest of the dishes . An air gap will form between the base of the pan & the Baking Soda / scum bussiness. I usaully use one of those long handled scrappy brushes to see if all of it came off . Normal this is good enough but having my skills it can last well into a second round .
I make a paste with Baking Soda and Lemon juice ....works everytime!!