Parchment paper is a gift from the kitchen Gods; it eliminates washing of pans almost entirely, and the non-stick, slippy but not greasy surface creates beautiful golden brown and toasty foods.
But... you're probably using it wrong. Oh; don't feel judged! Ripped and flat right from the roll works okay, but it's not the most effective pan liner when done that way and it won't cover up onto the sheet pan sides. Sometimes it slips around so much your chicken fingers or oatmeal chip cookies slide right onto the kitchen floor. (The dog thanks you, though.)
Here's what you need to do:
1. Rip off a length of parchment to slightly overhang the pan. Now, crumple it into a tight ball. Yep. Do it.
2. Now, take that crunchy ball of parchment and hold it under a cold running tap. Get it good and wet and squeeze it tight with your hands to squish the excess water out.
3. Gently un-crumple it and look at what you have there! A soft, totally pliable, almost-cloth like pan liner that can fold and be fitted right to your pan.
That's it! You're done! Go forth and spread this new parchment paper gospel.