Possible Clues:

• The whole idea of an electrical contact
• Tip for cricketer in the field
• Full stop
• The purpose of putting oxygen into beer?
• Use one's index finger
• Sharp end - purpose
• Mention, with ''out''
• There's nothing in a half quart to bring one to a full stop
• Look sharp at the end of your sentence
• Repair brickwork, using sharp end of tool