Hi Jasper:

You can use up to a quart of straight 'cheap' white vinegar or any kind you have on hand, it sure stinks up the house - so do it outside! (it will also chase the neighbors cats and dogs away! ¶…) you can even repeat it, if you want to be real sure it's clean (it won't hurt the coffee maker) -- then rinse with plain water, a few times - that should work.

If it's the pot and there is a residue or lime build-up, you might try a product called LIME-AWAY sold in most markets, in So. Calif at least.

Heat the pot with hot water, dump the water out and add the Lime-Away about 1/2 cup or as needed until the residue is removed.

The Lime-Away will bubble, sizzle and froth while it is working, when it stops the pot should be clean where ever the contact was, if not - repeat until it is clean, you may also have to tilt the pot to access up the sides etc.

A WORD OF CAUTION: Read the directions on the container,it contains acid, and may cause irritation.

And make sure you rinse 3,4 or even 5 times with clear, clean water before using the pot!.

jimS So Cal.