Related Clues:

• Inbox accumulation
• Shag carpet feature
• It may be down
• Large stack
• Carpet's characteristic
• Leaf collection
• Accumulate (with "up")
• Atomic reactor
• Professional organizer's target, maybe
• Load of loot
• Energy source since 1942
• Feature of a dirty desk
• Quite a tidy sum
• A heap or stack
• See 1 down