What about some florescent colored sand in a green color?
I really like this idea :3Or what about making the LABEL to be the invite info? That would be fun to write:
"TITLE of PARTY"
date time
Potion ingredients:
A small pinch of magic,
pointed hat and a broomstick
now we just need YOU
for the perfect brew!
Have a little oval aged paper label attached and have a little witch graphic, cauldron, or something as the center of the label, with the activities sort of circling the outsides. and the ingredent/address info on a backside label (so two labels, one front and one back, but would be a really cool invite)