A can of Tri Die will be fine to sit in your mailbox until you get home. You would just want to bring it to a cool temperature stable area once you retrieve it and keep it stored in that cool area throughout the duration of the cans use.
PT Tri-Die Pressurized Dust Insecticide is labeled for spo treating localized termite infestations as directed on the product label.
You should not apply PT Tri-Die Pressurized Dust Insecticide or other insecticides directly into an air vent. You could potentially apply this around the edges around the vent cover to treat into a wall void; however, you should not apply insecticides directly into any air vents.
PT Tri-Die Pressurized Dust Insecticide does not kill on contact. However, the pyrethrin in the Tri-Die will last for a couple of days but the silica gel will last until it is removed or covered up with debris. Please see our spider guide here for more info on how to treat and prevent these pests.
Tri-Die contains natural pyrethrin, which breaks down quickly in sunlight, and silica gel, a natural desiccant that would likely be washed away quickly. The PBO synergist in the product also breaks down quickly once applied. You can always use a hose to water the area to remove any residual product.
