Do you have the DCC-2000?
To delime a multi-cup coffee maker, mix white vinegar with water (1/3 vinegar and 2/3 water) and fill the water reservoir completely. Then turn the coffee maker on. Wait until the unit completes the "brewing" cycle and beeps 5 times. Turn off the coffee maker. Discard the liquid after the cycle. Then fill the reservoir with clean water and turn on again. When this cycle completes, again discard the liquid. Repeat the water rinse if you notice an odd taste to the coffee afterwards. (If the coffee maker still has deposits, repeat the vinegar cleaning cycle and rinse cycles.) There are commercial deliming products, mix them with water following the package directions.
The manual for the DCC-2000 is available as a link here: http://www.cuisinart.com/products/coffee_bar/dcc-2000.html
. The direct link to the manual is http://www.cuisinart.com/share/pdf/manuals/dcc-2000.pdf
I hope this helps.