Johnny Miller, Raymond HomMartha Stewart Living, January 2010
Work on a protected surface in a well-ventilated area. Clean glass before starting. Cover vessels' exteriors with paper, or remove glass from frame.
Spray interiors of vessels or frame glass lightly with water and then with mirror paint (the water will make the paint mottled).
Turn vessels upside down on a drying rack (so air circulates inside). Let dry completely, at least overnight. Repeat if too sheer.
For flowers, arrange in a glass and place the glass inside the vase.
Picture frames with glass
Spray bottle with water
Mirror paint (krylon.com)
Like magic, you can turn clear vases and candleholders into "mercury glass" and make plain framed glass look like an age-worn mirror. Just use mirror paint, and add water for a result that looks authentically old.