Well descaling a heating element is quite simple. A heating element can be placed inside a water tight tube. But the flange can not be submerged, the chance that water gets inside the heating element is possible. Which shorts out the element and makes it unuasable.
To descale a heating element you can use Puly caff Calcinet descaler , this need to be dissolved into hot water. First remove the loose lime scale. If it doesn’t remove all the limescale, repeat the procedure.