Since we got our first house I have done the similar ritual of taking
the bag containing salt, money, a piece of coal(that should probably
be a container of gas by now) and a loaf of bread out of the back
door, waiting until I hear the bells, fireworks etc signalling
midnight, and then ringing the front doorbell to be let in again.

I always presumed that this was related to the scots custom of
"first footing", my father always did it and I guess I just carried
on with the thing.

Doesn't help much but thats all I know.

Happy New Year to you all

Cattail !