crisgal
The Steradent solution i.e. drop one fizzing tab into the bottle helps to keep the pipes clean also because of it's 'designed' cleaning effect for grubby dentures.
btw this tip was given to me by an old garage hand who said thats how they dealt with people like yourself who came in with this problem.
x
Careful in using a needle as you can snap em off if the little ball is tight. If it just need cleaning out get a pair of pliers and pull out a bristle from a wire brush. Used this for years :)