It's simple, really. My Mother grew up in a poor immigrant Italian family in Hoboken. I'm sure her Neapolitan parents passed on this tradition. When you're poor in Italy, you are superstitious about money so you tend to push luck on your side with certain traditions. You would eat coin shaped lentils on New Year's Day, for instance. My Mother taught me that putting a pile of coins--whatever you happen to be carrying in your pocket at the end of the year--on the windowsill will guarantee that you have money all year long.
One rule: Put the coins out before midnight.
Felice Anno Nuovo!
Years ago when I lived in my loft/studio in the Flatiron district of Manhattan, I used to have my windows washed by professional window-washers. You know the kind... they clip their safety belts on to lugs outside of the commercial building windows, then lean back over the void to soap up, clean and then squeegie the windows clean. I had a 50 foot long wall of 10 foot tall windows running along the front of my sixth floor loft. Once a month, they would clean the city grime off the windows and suddenly the front of the studio would seem a lot brighter.
One year, in a cold January, I noticed that the years of accumulated nickels, dimes, pennies
and quarters were gone! There must have been $20-30 in coins out there. I figured one of my window-washers must have needed it more than I did...
...unless it was those notorious, thieving Flying Rats of New York--the pigeons!