Stuffing them with fabric gives them a finished but soft look.
You will need:
scraps of t-shirts in the colors you want
hot glue gun
dremel or drill (optional; I drilled holes in the caps so I can string these on a garland)
Step 1: Drill Caps
Find a dremel or drill with a small drill bit. Hold the acorn cap steady and carefully drill two small holes at the top (to pass the string in and out).
Clean up any acorn dust so it doesn't get all over your t-shirt fabric.
Step 2: Cut T-shirt Pieces
Wad up the stuffing, place it in the center of the circle, and gather the edges of the circle around the stuffing to make a little sack.
Step 3: Glue
Squirt hot glue into the acorn cap around the inside edge. Avoid getting glue near the drilled holes if you want to string these when you're done.
Press the stuffed fabric firmly into the acorn cap, making sure all cut edges are firmly glued inside and not showing. Squish the fabric ball to minimize any folds showing.
I sprayed these lightly with metallic spray paint because of the party's color scheme, but you can just as easily leave them unpainted.
Thanks for reading!