Several dehydrate in the open, perhaps (6)
I believe the answer is:
sundry
'several' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for sundry that I've seen before include "Various, assorted" , "Of various kinds" , "All and . . . . . . - various or several" , "Assorted objects" , "All and . . . . . . means everyone" .)