DIY might be suitable. They have an appliances tag
For questions relating to powered consumer products that perform some value-added task within a home, including but not limited to hot water heaters, stoves/ovens, dishwashers, refrigerators, etc. For questions specifically relating to furnaces or air conditioners, see the "hvac" tag.
There's at least one question about kettle scaling that's not closed.
Check out the site's help centre and maybe try it's meta if you're still unsure.
If that DIY doesn't fly then lifehacks may suggest some clever workaround to get the job done. They certainly have questions on cleaning things and a cleaning tag.
The lifehacks cleaning tag description is
Tips and tricks relating to cleaning clothing, objects etc. quickly and easily. Please also use another applicable tag (e.g., [clothing], [kitchen], etc.), as THIS TAG IS AMBIGUOUS.