I do a lot of hunting and there are suits you can buy that are supposed to reduce human scent. But according to the manufacturers and articles I've read on carbon it requires a person to 're-activate' the carbon granules after they've been saturated with whatever scent molecules it's being subjected to. Re-activation is accomplished by heating the garments/carbon. This process 'burns off' the scent molecules by the heating of the carbon. They suggest using a clothes dryer to do so, but carbon, to be cleansed of scent molecules, requires far greater heat than a home clothes dryer can attain. Anyway, that said, it would seem that carbon filters used in the reduction of the smell of mj would also need to be 're-activated' or replaced often. More often than would be financially feasible as within a few minutes the carbon will have absorbed as much/many scent molecules as it can hold and not be able to control the smell of a flowering plant. Carbon is like a sponge. It doesn't destroy scent, but holds it. So I wonder how it's working for the time span that most use them? Sometimes for months. I've never used one though so I'm just offering this info for...who knows why.