Related Clues:

• Recharge one's batteries
• Additional ones not itemized
• Move to first class, e.g.
• Type of mollusk
• Stop arguing
• Good secret-keeper
• Place for steamers
• Reason for a stop
• Whatever's still there
• Unused portion
• Stand still
• See 51 Across
• Chowder mollusk
• Freedom from activity
• Kind of dip or diggers