1 See if the outer packing is exquisite. The bottles of general brand drinks are all of good texture, and the outside is smooth without plastic burrs.
Too full or too little must not be true. Because manufacturers will never use different machines to fill cans during production, nor will they fill them, but they will leave some space, and each bottle is the same.
The date of production on the bottle cap is very clear (sometimes only half, completely invisible. But what you can see is absolutely clear. Most of them are fakes, because the paint they use is not good and wears off easily.