My eighteen year old le crueset has had enamel that is grey and lost it's luster years ago and still is fine and don't plan on replacing yet. Also, a capfull of bleach helps in the soaking process for getting burnt food to unstick and disolve. @FrsehMel leave the advice giving to those who really know! If you don't know an answer, don't answer!

you all are amazing as one collective, peer resource. i've since made a new batch of soup in it, and no one dropped dead immediately. hopefully the long-term effects of a greyish bottomed pot will not do us in any time soon, either... and there's no charred taste at all (i first tested that by sipping water that had been boiled in it). and yes, i like antoniajames advice about embracing this imperfection...i'll be embracing this one, and lots of other dings and stains and visual cues to past missteps... :)

Don't you just hate when that happens? I did it with split pea soup in stainless steel and did the baking soda trick followed by Bar Keeper's Friend for the detail work--don't know who discovered particular hint from Heloise, but I love that person.

Awww, AntoniaJames, that's a beautiful answer. Who, besides the cook, sees the bottom of the pot?

I've had success getting burned residue out of stainless pans by boiling a cup or so of water and a half-cup of baking soda until the water is gone and the soda dry and cracky...then it peels out with the burnt stuff adhering. Might work on the stains, not sure!

I don't know if this will work on enamel, but if I leave plastic ware in the sun, the stains come out. Boiling water seems a good idea.

I have done this before too. Try and fill it with water (80% full) and a few drops of dish soap. Boil it for an hour, covered and most of the charred bits will come off, the water should turn dark as well.

You will never be able to get it sparkling white again but it is safe to use. Scrub it (not scour) with Bon Ami or even Comet, but you are still going to have darkness at the edge of town.

almost impossible to hurt a Le Creuzet. Soak and wash, but the patina on ours has posed no issues for many years.

Don't worry about discoloration. Embrace it. It shows that you're using the pot, that you're human, and that life is much too interesting and you have far too many other, more important things to do than to clean (or worry about) the inside of your pots. ;o)

thanks so much! i may try to contact le creuset directly. surface doesn't seem to be damaged physically, so much as discolored. so sad. i've tried a little bleach and hot water, i've tried scrubbing with bon ami, soaking with white vinegar...

I've done some very very mean things to my le creuset over the years - I would soak it overnight, starting with some hot water and baking soda. You may need to do it a few times, but that's how I've eventually gotten mine clean. If all else fails, you may want to contact le creuset to see what they say. The link to their care recommendations is here:
http://www.lecreuset.com/en-us/Care--Use1/Cast-Iron/

If the enamel coating (the ivory, glossy interior) has been compromised, than I would consider it unsafe to use.

I would say yes. Consider it well seasoned :) Cook something you'd like to have a smoky flavor!