I have a live trap that I use to relocate unwanted animals. They are not overly expensive and are useful for trapping domestic strays as well. Outside of that solution, there is the pellet gun, which is harsh, but I can't believe that any kind of spray, pellets, or treatment will be overly effective. Everyone has seen those old cartoons where the chipmunks are chattering and laughing at their mischievous antics. I don't think that presentation is too far from the truth.
Eclectic gardening style, drawing from 45 years of interest and experience. Mostly plant in raised beds and containers primarily using intensive gardening techniques.