well, im sure if you used rubber sealants/silicone for a more permanent seal, and then flushed the area with alcohol of a sorts to dissolve and rinse the thc off, and then washed it with higher pressure water, like what comes out of the jet nozzle on a hose then the smell would be pretty well contained, especially if its done so that you can hide weed in it and remove it, i mean the smell cant travel that well through thicker molded plastic, and metal is rather tough, but take extra precautions to make sure there arent any holes, like at the ends of the tubes.