Hairy layer (4)
I believe the answer is:
fuzz
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">hairy layer</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for fuzz that I've seen before include "Old Bill (slang)" , "Frizzy mass of hair" , "lack of clarity" , "Soft, fine hair; blur" , "Frizzy hair; blurred image" .)