It's a term used for bolt cutters. Homeless people, or those individuals who stay in the streets late at night refer to the phrase of having the proper tool used for breaking into things such as metal fences, gates with wires and locked chains that bolt cutters are capable of cutting through.
Hey bro, I saw two of these really nice mountain bikes locked up over on 16th St. If you can burrow your uncle's Keys to the city, we can swing by there later on tonight and snatch us up some new wheels.
During the evening, when I get tired, and I'm done pan handling for change, I go over to this abandoned building with a gate surrounding it to get some rest. I used keys to the city to cut through the gate as an entrance to sneak in.
Fogey/fogy /fougi/ sl. (early 18C+, orig. Scot) old-fashioned, stuck-in-the mud.
Person with old fashioned ideas which he is unwilling to change: Come to the disco and stop being such an old fogey!
You think me an old fogeyand an old tory, his thoughtful voice said. I saw three generations since O’Connel’s time. I remember the famine. Do you know that the orange lodges agitated for repeal of the union twenty years before O’Connel did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things. (James Joyce, Ulysses. Penguin Books,1992. p. 38)