I grew up on 4th Avenue in Bay Ridge, Brooklyn. The R Train (4th Avenue Local -The “RR” or Ridge Runner back then) traveled the length of 4th Avenue to 95th Street. Every other block had subway ventilation grates (known as the “subway gratings”) on the sidewalk near the curb. People would drop coins and other “stuff” down there. To get them out, you assembled a “fishing” kit:

A 3 ounce lead fishing sinker
A ball of string (kite string was good)
A jar of Vaseline

Take the lead sinker, and scrape and smash the pointed bottom on the sidewalk until it is flattened.
Our string used to be wrapped around a small stick.
Tie the string on the sinker, and dab Vaseline on the flattened end of it.

Walk along the gratings until you see a coin. Lower the sinker, and moving carefully, hover just above the coin. When the sinker steadies, drop it on the coin. (Here you have to be careful… if you miss, the sinker will hit the bottom of the air shaft and the Vaseline gets full of dirt and loses its stickiness).
After “catching” the coin, pull it up slowly… if you go too fast, the coin will fall off.

Many times you would get a coin all the way to the top, but when maneuvering the sinker and coin through the grating, it would hit the side and the coin would fall off.

There always seemed to be lots of coins nearer to Bay Ridge Avenue (69th Street). The local lore had it that people rushing for the train would drop their change.