All you need is 2 cups of white vinegar and fresh water ...
Clean a coffee maker by ...
1. Pouring the vinegar into the reservoir and top it off with water. Turn on the coffee maker and let it brew a cup of the vinegar and water mix.
2. Turn it off and let it stand for half an hour.
3. Turn the coffee maker back on. Let it finish brewing the pot of vinegar and water, then empty the pot, rinse it out, and fill the reservoir with fresh water. Brew the pot of water without interruption.
4. Empty, rinse, allow the coffee maker to cool a nit, and then brew another pot of water.
from Organic Housekeeping by Ellen Sandbeck, p. 96