Frequently used by my Texan ex-gf, specifically in the context of letting the dog have them.
ETA: But never heard of by myself before then.
Yup, I have heard it and use it on occasion. My dogs know what pizza bones are. 
Another hand in the air for this.
Heard it plenty, southwestern US. From the various kids in my family, I’ve also heard the crusts referred to as the “skins”.
What he said.
Concur with Mr Shine.
I guess I should have said “common term among people I know personally in Toronto”. 
I and others used the term while in college during the 70’s, Baltimore. It referred to the uneaten crusts.
T ain’t no sin to take off your skin
And dance around in your bones.
just sayin.
Yes, since college in the Midwest. When you hear it in context (over a pizza) you’d have to be thick (crust) not to get it.
True enough - but to be fair to the guys, they got it quickly enough - they had just never heard it before.
A married couple I’m friends with uses that term: I’ve never heard another person use it, and I’d never heard it before I met them.
Background: I’m 41, grew up mostly near Baltimore, lived in England as a kid, went to college near Philly, and am currently living near DC (oh, and my extended family lives in New Jersey/New York).
Call me a deep dish, then, because the first time I heard one of my friends say it I had absolutely no idea what he was on about. We were eating pizza at the time. 
It made sense as soon as he 'splained, though.
I’d never heard of it, but I have used the phrase, thought I made it up! The way they’re making pizzas around here with skimpier toppings, there’s a whole lot more bones than pizza. If the crust is good, we’ll dip them in blue cheese or Italian dressing, like breadsticks, otherwise, throw them out.
Since when? I don’t mean that in a challenging, snarky way. It’s just that I grew up in SoCal with pizza being my most favorite food EVAR! and never heard the term until I moved to the southeast and even then I don’t hear it much.
It was a common term when I was school in southern California in the 1980’s. We also called the inedible stems of grapes as “the bones”.
Never heard it before. Grew up East Coast of US, now live in Pacific NW. I’m craving Pizza now, though.
Never heard it before, but I like it. Will use in the future.
Nope, never heard it before. Why didn’t you make this a poll?
I’ve never heard it before, but I guessed what it meant.
Yeah, I thought about it after - would have been easier to tally.
I’m not sure, but maybe I can still add one… there we go!