And here's another one:- I'd had this idea myself but thought the master & Mistress's latch pin would hardly have a silver head but this verse comes from 'The Wassailing Song' but the site doesn't give it a locality.

Then here's to the maid in the lily white smock
Who tripped to the door and slipped back the lock
Who tripped to the door and pulled back the pin
For to let these jolly wassailers in.

J