Slough off skin of ram or asses (6)

I believe the answer is:

morass

I'm a little stuck... Click here to teach me more about this clue!

'slough off skin' is the definition.
'morass' can be an answer for 'slough' (I've seen this before). I am unsure of the 'off skin' bit.

'of ram or asses' is the wordplay.
'of' indicates the answer is hidden within the clue.
'MORASS' is hidden within 'ram or asses'.

Can you help me to learn more?

(Other definitions for morass that I've seen before include "dangerous situation" , "Bog or marsh" , "Area of marshy or swampy ground" , "Confusion" , "Tract of swampy land" .)

I've seen this clue in the Sydney Morning Herald.

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