If you have stickers sheets that have a colored background (white is ok too!), save those bits for punching!
If a shaped punch or die cut will fit in the spaces- GREAT! Use that! If not, use a regular hole puncher to use those bits up!
For this holographic sheet here, I used a hole puncher to punch out tiny circles that work great as bubbles for my under the sea pieces.
I recommend investing in one or two mini shape punches that you would use a to get the most out of your scraps. I personally have a star, a hear and a circle. You can punch them all once, store them in a bead organizer and have all sorts embellies ready when you need them.