I assume you mean descaling the coffee maker when the Clean indicator flashes after a brewing cycle. You can use a packaged descaling product or white vinegar. For the packaged descaling agent, follow the package directions for the ratio of product and water. If you are using vinegar, fill the carafe with a 50:50 mixture of water and vinegar.
Remove the water filter and remove any coffee and coffee filter from the brew basket. Make sure the unit is plugged in and turned on. Pour the descaling mix from the carafe into the water tank and then place the carafe in the coffee maker. You have 10 seconds to program the cleaning mode or the unit will return to the standby mode. The next step depends on the type of carafe. For a machine with the glass carafe, press Mode 6 times. Otherwise for a unit with the thermal carafe, press Mode 5 times. The Clean indicator will blink. Press Program/Set followed by the + or - button to select Clean On. Press and hold Program/Set until you hear the beep. Press Brew and wait for the cycle to complete (the Clean indicator will go off). Then do two brewing cycles with water but no coffee or coffee filter. Discard the fluid from the coffee maker from all three cycles. Wash the brew basket and then reinstall the water filter.
If you notice an odd taste to the coffee when you next brew some, do at least one more rinse with water (remove the water filter and coffee grounds/filter).
KitchenAid manuals are available from their site: http://shared.whirlpoolcorp.com/product_literature/search.jsp?siteCd=KAD
. The direct link to the manual for the Kitchenaid KCM223OB is http://www.kitchenaid.ca/assets/pdfs/literature/Use%20and%20Care%20Guide%20-%20W10321647.pdf
. See page 13 for the directions.
I hope this helps.