Tin Whistle Maintenance
The beauty of whistles is that other than a little cleaning, very little in the way of instrument maintenance is required for the owner of a tin whistle. If your whistle's condition is ever diagnosed as terminal, a $10 replacement is readily available and can get you “good as new ” very rapidly.
Getting inside to clean a whistle tube and mouthpiece is very difficult if you do not have the ability to remove the mouthpiece. [If your whistle has a glued-in plastic fipple, check out the Home Surgery section below for tips on how to remove it.]
As is the case with all mouth-blown instruments, the interior of a tin whistle presents a wet and humid environment due to the condensation of your breath as you play. The dampness in turn attracts and retains dust and dirt. To clean out the dust, remove the mouthpiece and twirl a dry cloth from one end of the whistle body through to the other end. Then clean out the mouthpiece itself with the cloth. To keep moisture out of your whistle's way (and sound better), you can periodically clear the mouthpiece by manipulating the blade of the mouthpiece with your finger and blowing hard through the fipple a few times.
Home Surgery: Making a Plastic-Fippled Whistle Tunable
Let's suppose you just purchased the typical starter whistle with a plastic mouthpiece. Your very next step should be to remove the glued-on mouthpiece. This will accomplish two objectives—it makes the instrument tunable, as well as far more accessible for cleaning.
To loosen the cement holding the plastic mouthpiece in place, dunk the mouthpiece end of the whistle in a cup of hot (not boiling) water for 15 seconds. [CAUTION: If the water is too hot, it can warp the plastic and damage the fipple.] Once you have removed the mouthpiece, you can use an X-acto blade to trim off the residual cement. Examine the mouthpiece for any manufacturing defects; i.e., minute fragments of excess plastic that can make a whistle sound more scratchy. Taking care to steer clear of the thin plastic blade of the mouthpiece, you can also use an X-acto knife to trim off any excess plastic remnants you find and smooth down the plastic on the inner sides of the mouthpiece.
Now that you have made your mouthpiece removable, you will be able to move the mouthpiece forward and back slightly. Moving it forward lengthens the whistle, lowering the pitch; moving it back shortens the whistle, raising the pitch. In the sense already described, your whistle is now tunable. If you find the mouthpiece to be too loose at this point, visit the plumbing section of your hardware store for some Teflon tape, which you can use to fine-tune the tension between the fipple and the whistle body. In most cases, you shouldn't need any more than a very small piece of tape to tighten up the mouthpiece.