YA Fiction - boy rubs potion on shoulders & grows wings

I keep remembering then forgetting the name of this book -- my older sister had a copy of it twenty-thirty years ago when we were growing up. All I remember is that a boy found a bottle of some sort of potion, would rub it into his shoulders and grow wings, so then he'd go out flying around his town at night. Does this sound familiar to anyone?

I think it's Black and Blue Magic by Zilpha Keatley Snyder.

Definitely Black and Blue Magic. I ordered a copy online a couple years ago, loved that book as a kid

Yep. A Frequently Sought book, and a great one. I finally locked down the title in my memory by visualizing him landing and barking his shins on the windowsill (which he does, a couple times, I believe) - he ends up thoroughly bruised, thus the name of the book.

Yes, that's it! thanks so much - I've been trying to remember the name of this book for so long, and now I have it. Wonderful.....