Here is a great article for beerstone, you will still have to scrub, but it works, I have used it to remove it from the chiller coils on my Spike Conical Fermentors.I haven't found a solution for beerstone yet. Beerstone remover doesn't work. LLC doesn't work. Star San doesn't work. Citric acid certainly doesn't work.
https://www.birkocorp.com/wp-content/uploads/2017/08/Birko_Removing_Beerstone_Article.pdf