Benf15harp
Well-known Member
Post office isn’t customs100% sure there are portable chemical analysis spectrometer's that customs for example uses. They are used for initial identification of an unknown substance and then they often send it off to a lab for a 100% conformation. The good ones aren't cheap, but they do have them. Basically over-simplified they can blast the substance with light and see how much gets absorbed and every substance has a bit different of a pattern. Then then can compare this pattern to a huge database of known chemicals.