Wait what? Seriously?
Have a fucking tube sale. Pepper in some good stuff from the archives to whet people's appetite and then let it rip. I've printed 100's of posters by me and other artists, and I've never had to throw a poster away. From Test Sheets to scratch/dents, to stuff that just plain didn't sell- I've never not made money on a print.
Even if you just put a random extra print in each tube for stuff you do sell, you'll go through it all, and make people happy...why throw it away?
This business is a battle of inches (or pennies in this case) don't let shit go to waste!