If it is absolutely in need of cleaning, by all means use a cap or two of bleach and hot water... Then I use hot water with some baking soda and white vinegar, let it sit.... don't let it get cold though. And finally baking soda and lemon juice. When you put the vinegar or the lemon juice in with the baking soda, it will fizz a lot, so make sure you leave some room for expansion, don't totally fill it. I usually do the lemon juice and baking soda, but will resort to the other methods if it really needs a good cleaning.
Make sure you let the water go through the tube to flush that out as well.... then finally rinse it out with hot water and let the water go through the tube again, I usually fill and pour out about 3 or 4 bag fulls of hot water.
