we had same problem this summer and i found the easiest/safest way is
using liquid "Lime Scale Remover"  from the hardware store.  wipe it
on with a cloth and wipe off with fresh water then paper-towel dry.
Vinegar didn't quite do the trick for some deposits. I don't know what
acid is in the Lime Scale Remover but it's quite strong so avoid
getting it on skin, in eyes, on other things, etc.

alan