Your answer about the plastic teakettle that needs to be toveled is puzzling to me, since by toveling it, the electric unit can be harmed. I have several electic appliances that I understood couldn’t be toveled because of that reason.
I did it personally to a new kettle I bought last Friday, I Toveled it in the Mikveh, put it in the sun for a few hours and used it all through Shabbat without concern. A professional electrician told me it's no problem because it's a simple electric system, and not gentle circuitry vulnerable to water. Anyway, if you are still concerned there are two more options: I. Give it to a Jewish electrician to disassemble and rebuild, then the utensil will be considered Jewish made, or II. Give it as a present to a Goy and ask him to lend it to you for use, and of course you continue using it eternally. (The Goy doesn't have to understand exactly why this is done). Rabbi Ro'i Margalit