unclear arthur's method takes to long. Next time, take some Comet and Bleach and put them in the toilet and swirl it up with the brush (don't be a pig, make sure the toilet is empty of anything unsavory when you start this). Then take the stem off the pipe and shove it in the the Comet/Bleach slurry and flush. Use the swirling jet motion of the water to completely clean the stem. If it takes more than one or two flushes, you are doing something wrong.