Dogs have an incredible ability to sniff various things around their surroundings. However, there are some materials that a dog cannot smell through, like air-tight containers or vacuum-sealed containers. However, it depends on the material of the container.  For instance, if the container is plastic, it is a porous container. The odors can seep away from the microscopic holes, and your pooch can easily catch the scent. But if the container consists of glass or metal, then the odor cannot escape from it, and your dog cannot be able to detect it.