Many bugs find the scent of essential oils repellant. Roaches are no exception. You can create your own homemade roach spray using completely non-toxic essential oils. The most effective oils at repelling roaches are cypress oil and peppermint oil. To make a non-toxic roach spray, mix 8 drops of cypress oil and 10 drops of peppermint oil to half a cup of water. Spray the mixture anywhere you have roach issues. The added benefit is that these oils smell lovely. No gas masks required.