Don't you love the sound of the Sapper Kettle?
Alessi refers to these as the E & B Pitch Pipes. Over time, impurities in the tap water corrode the internal reed whistle, and always the low pitched one first. Here's a tip: Once replaced, avoid overfilling the kettle to the top, causing boiling and water to spill though the pipes. The water might contain impurities, but the steam doesn't. This should help keep the pipes in working order for many years. We've had our Sapper kettle for 30 years.
I have found the best way to remove the old whistles is with the thick end of a Chop Stick. The soft wood worn't scratch the metal. Insert chopstick from the bottom and tap to drive them up and out from the top.
I get my replacement Pitch Pipes at the San Francisco Alessi store: Part 12701. Cost: approximately $16. (415) 434-0403 [email protected]
Hope this helps.