Re: Whistle Maintenance.

In getting stuck things apart one consideration that can help or hinder is the coefficient of expansion of different metal. In simple terms different metals expand to a greater or lesser extent than others when heated the same amount. In the case of getting a steel screw out of an aluminum or brass/bronze article, by heating the entire part evenly the steel screw will end up loose because steel expands less for the same amount of heating. This is very helpful if you happen to be restoring old gas engine magnetos, or carburetors. A stuck steel bolt in a "brass whistle" would be the same. A brass washout plug in a boiler that can't be removed by the longest cheater bar can be loosened up by heating it. One would presume when it is heated, it gets tighter, but after it cools it generally will come out, probably because it had to deform a bit under the pressure created when it was heated and the corrosion that held it fast is broke loose.
When I deal with delicate brass or aluminum items that I want to heat I often use a prestolite torch or a propane torch as the heat is a lot less, and it minimizes the idiot factor of overheating and making marks on the item where the metal was hot enough to flow. I have screwed up and made torch dimples this way more than once using an oxyacetylene torch on brass.
As a penetrating agent I have had good luck with a product by Schaeffer Oil called Penetrol 90. Again good luck with your whistle.