A container assembly includes exterior storage recesses or other accommodating spaces or members into which one or more cartridges may be removably inserted for the storage of chemical compounds. In various embodiments, one or more storage containers may contain a liquid and a solid component or a crystalline or powder and a solid component to be mixed in an interior of the container body, for example with water or other liquid, to form an activated compound. That compound or solution may be or include a pesticide, herbicide, fungicide, fuel mixture, cleaner, or other end product. The storage cartridges containing the ingredients may be configured to threadedly engage an outer cap which attaches to an opening in the container body. The outer cap and the threads of the ingredient-storing compartments may be counter threaded, so that when the outer cap is attached to the attachment opening of the container body, the storage compartments detach and drop into the interior of the container, releasing the ingredients for mixture and use. The separation of potentially volatile ingredients improves the shelf life of pesticides and other end product or solutions.