Possible Clues:

• Use a microdermabrasion agent, say
• Use pumice on, perhaps
• Remove dead skin
• Make flow of latex, ie discard bark
• Use a chemical peel
• Some detail of xenophobia, being brought up in Slough
• Shed in flakes or layers
• Flake off, dripping round oil spilt in river
• I exalt foe disposed to save his skin!
• Come off in flakes or layers