White spots inside an electric kettle? Philips' scale-removal steps
White spots on a kettle's element can be mineral scale. Philips recommends a suitable descaler or a model-approved vinegar/citric-acid routine followed by thorough rinsing.
Philips support explains that mineral scale on the heating element is common and depends on water hardness. Exact acid concentration and quantities vary by model; this is a model-dependent example, not a universal recipe. Avoid scraping the heater or mixing chemicals.