|KELLY'S CRAFTS-Stain Pens. This package contains eighteen fascinating stain pens for use on glass; acetate; plastic; plexiglass; mirrors and even metal. It is so easy to make your own suncatchers. Contents conform to ASTM D4236. Recommended for children ages 5 and up. WARNING: Choking Hazard-small parts. Not for children under 3 years. Imported.