This topic is a bit old, but I've ran in to the problem of water bottle cleaning before. I used to fill the bottle with hot water and use a tooth brush to clean the inside (a clean toothbrush, not the one I use everyday
) this worked extremely well and then I would just put my finger over the opening of the bottle and shake it. Then I would empty it while shaking it.
Then for the nozzle I would pull the rubber ring out and run that under water between my fingers to get it clean. Then using a Q-Tip I would clean the inside of the tube. I don't really like this method as pieces of the Q-Tip head can come off, but I haven't found anything else to use yet.
I also like to keep a second bottle on hand, then if I have to soak the bottle for a day or so to clean it, it has plenty of time to soak and dry and my pigs can still enjoy water.