Decorate pretzels. Reheat reserved candy, if necessary. Fill parchment bag half way with melted candy; cut small tip. Pipe shamrocks in center of coins. Chill until set, about 10 to 15 minutes.
Place coins on fresh sheet of parchment paper. Spray with Gold Color Mist Food Color Spray. Repeat if desired. Let dry, about 5 to 10 minutes.