Quote from: zifnab on March 05, 2012, 12:53 amQuote from: topia on March 04, 2012, 10:55 pmI wonder if an electronic 'nose' would be able to sniff the difference between carbon and activated carbon, vs carbon from pencil lead, or even carbon used in the ink on the package's label, or carbon from "roasted cacao beans" (that's what you declared for customs, right?)Maybe.Fast shipping plus stealth packaging works for now, as far as I know.Carbon is carbon is carbon; it all smells the same unless treated. Activated carbon works by trapping molecules in tiny holes that run through the granules like swiss cheese. Since different molecules have different sizes you have to pick you grade of activated carbon based on the molecule(s) you're filtering our. If its more than 1 kind of molecule, you'll need a mix of grades in effective proportions.Perhaps this is a bit of a reach, but there are different isotopes of carbon. Now, it doesn't make a difference chemically maybe, but who is to say that a electronic nose can't distinguish different isotopes with some mechanism. And maybe activated carbon has a special isotope...Again, this is speculative. In any case, if you vacuum pack the activated carbon on the innermost layer of your triplicate or quadruplicate HDPP sealed packaging you should be fine for sure. I'd like to see a test for A-carbon to see how many nanograms per second leave the bag.