Course of salts? (5)
I believe the answer is:
epsom
I believe this clue is a double definition.
'course' is the first definition.
(I've seen this before)
'salts?' is the second definition.
(I've seen this before)
'of' acts as a link.
(Other definitions for epsom that I've seen before include "place for racing" , "Poems about English Derby venue" , "English town, of course?" , "Surrey race course" , "Mares would triumph here" .)