Paper container (8)
I believe the answer is:
envelope
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">paper container</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 envelope that I've seen before include "Cover for letter" , "Mailing item" , "what's to be posted in here?" , "Coat" , "note might be put into this" .)