Save descaler
I descale my kettle once a week with dilute liquid citric acid (as that does not stink as much as vinegar).
Then I fill the cooled solution in an empty bottle and use it again.
I can not say yet how many times that works with the same solution, I am currently at the 5th time. The lime is still dissolved perfectly.
So far, the solution still looks "clean". But if she looks unappetizing, I'll pour her into the toilet.
Since liquid citric acid is not cheap, it annoys me that I have not thought about it for a long time. But better late than never.
