Nicotine Water
Take 10 crushed cigarettes or 10 smokeless tobacco pouches and soak them in a half gallon of water. Let stand for about 30 minutes and strain the tobacco, paper and filters from the mixture with a cheese cloth. Add a teaspoon of dish soap to the mix and pour into a spray bottle. Spraying directly onto the stink bugs will kill them, and the residual poison will last for a few days outside.
Chrysanthemum Spray
Remove three blooms from any chrysanthemum bush and let dry. Crush the petals, stem and bulb in the center of the bloom into a container until it is a fine powder. Pour the powder into a spray bottle and add a half gallon of water. Shake the bottle well and spray onto areas where you have seen, or smelled, the stink bugs. The resultant spray is a Pyrethrin-based insecticide that kills most insects instantly on contact. Pyrethrin is the natural insecticide chemical in the Chrysanthemum flower. Since it is a natural insecticide, the effectiveness of the spray wears off on surfaces after a few days and won't harm the environment. Don't spray honey bees or any other beneficial insects.
Soap Water
Use a cheap generic soap and mix one part soap with one part water. Pour into a spray bottle and hose the bugs and the places you have seen them, and spray a barrier around every door, window and opening in your home. Even the most ineffective dish soap will kill a stink bug when used properly.
Prevent Infestation
One method is less a recipe than it is prevention. Stink bugs are attracted to both light and heat. Unlike other bugs, they have a knack for finding those cracks and crevices that lead into your home with just their natural heat sensors. Caulk off these areas with silicone sealant around windows, doors, eaves and chimneys. Install new screens to replace worn ripped ones.