CLR. Just be sure to run a full (coffee-less) cycle afterwards.

Vinegar will work, too, but not just by soaking. Run it through a cycle in the coffee maker twice. Fill it 1/4 full of vinegar, then the rest with water.

put some hot water in the bottom and swirl ice cubes around in it. the ice kinda scratches the gunk off

i've heard two things... warm/hot water with a little salt or vinegar

Best thing to do is to put in some baking soda with that vinegar. It'll fiz up and probably overflow, but that's ok. Let it, then shake it vigorously and let it sit for a few minutes.

Then dump it out and put in warm water and more baking soda==a tablespoon or so. Shake it vigorously and let it sit overnight. The next morning rinse it and it should be clean and fresh smelling. If not repeat until it is. It will work.

Good Luck

you put ice cubes in it and gently swish around the inside with a circular motion. No too hard it will break the glass.

In Wal-Mart they have a wall of brushes etc., one of which is designed to fit inside the likes of your carafe. I recommend you use a mix of 1/2 cup bleach and the rest water. Let is sit overnight and pour out and do a really good soapy water wash and rinse before you use it for coffee. Use the brush if there is a spot that's a build up of calcium and try scrubbing. If you have chunks of calcium build up then you can try the C.L.R., or vinegar as they'll break down the calcium. Good Luck.

How much would it cost to buy a new one? Your time might be more valuable than the cost if it's that "baked on."

Try filling most of the way w/hot water and add some bleach, then let it set for awhile. Be sure to wash & rinse thoroughly before using. Don't run this thru a coffee maker tho'. For that, use vinegar.

This REALLY works, so try it. No scrubbing. Doesn't matter the size of the opening. I've used it on my coffee carafe and also thermos bottles.
Buy a bottle of Greased Lightning. Simply spray it into the carafe and you'll see the brown stuff role right off! I've even used it at work on the Bunn machine's carafes, and those get really disgusting. It works like a breeze!
You can use Greased Lightning on lots of other things too, so it'll be good use of your money!

Try putting some baking soda and ice cubes down in the carafe. Let the ice melt alittle then swirl the ice cubes around in the baking soda. It should take away the stains. If all else fails, time to get a new carafe!