Possible Clues:

• Squirrel's discard
• 'Holder' of a brief explanation
• Crazy, horrible place for summaries?
• Model of brevity
• "In a ___ ..." ("To summarize ...")
• In brief, a skull
• Something to crack
• Fruit's woody covering
• She will go after teachers in case of compressed information
• To cut to the chase in this, deranged Old Nick's here