How to Tell If a Flask is Fake

Determine the era in which the flask was designed. Each era will provide insight into the type of technology that was available at the time. For example, most flasks manufactured in the 19th century were made from either glass or steel, each with a manufacturing technique distinct to the era in which it was produced.

Determine if the flask's material is designed using the technology of the era. For example, glass-based flasks designed in the early 20th century were made using blow machines, a technique that leaves a distinct look to the flask.

Determine if the material is fake. A distinct attribute of a fake flask is using knock-off materials. For example, a real silver flask will contain the following marks: the numbers 925 labeled somewhere on the flask, black stains indicating the chemical reaction of silver to heat and the ionization of sulfur molecules to silver molecules to create a darker black stain.

Determine the characteristics of the manufacture. If the flask was made from a particular manufacturer, glass-maker or blacksmith, often initials, logos and symbols will be stamped on the flask. Most popular glass-makers and blacksmiths who designed flasks initialed or signed the flask to indicate its authenticity.