To make one, you need:
An 8 x 10 photo frame with a removable back and removable lass.
Black high-gloss paint (not spray)
Dried psychic hers: hyssop, dragons blood, orris root, anise seed, or any type of dried moss.
A disposable mixing container.
A paint brush
Collect the items during the waning phase. Mix paint and herbs together until you have a thick tar like substance. Chant while mixing.
"Vision of night, by the moon's dark light, enter my art...anl evil depart.
As you chant, imagine moonbeams entering the pain through your hands. Paint one side of the glass with the paint herb mixture using long straight strokes. Cover one surface completely leaving no holes. When dry, re-assemble with painted side down.
Now you are done or you can add shells, stones, feathers, mirror pieces, symbols around the edges.