Best suggestion is do not buy another Keurig.. For one thing those coffee pods Green Mountain sells (K-Kups) do not break down in land fills and are thus a major solution source. (you can get bio-degradable ones from other companies but I don't care for the coffee that much, You can also get resuablee (Cups) (put in your own coffee) but if you do that why have a Keurig?
You can also get 3rd party automatic drip coffee makers that can accept K-Kups I have seen one by Sunbeam and another (Which I have) in a store called Freds. 20 bucks as I recall.
The other reason to avoid Keurig is that, as you discovered, there is no way to completly empty them of water. Thus the water remains in them all the time, If not used often the water gets stagnant and of course in your case.... Well,
The automatic drip makers do boil off all the water.. So that's not a problem.