Possible Clues:

• Open, say, with a pin
• Pinned ornament
• Said to open up with a pin
• Adornment for dress
• Your little brother? Och, he has a point, but there's a catch in it
• Clothing ornament and ring found in ancient tower
• Nothing found in old Scots castle but an ornamental clasp
• Pin one down to open one up, by the sound of it
• Ornamental hinged pin
• Jewellery item with pin