By Lauren Shanesy For some retailers, a car wash is nothing but the “building out back” (or as some operators affectionately refer to it, Bob). A car wash can offer significant profit margins for retailers, but it’s not passive income. Running a car wash requires intention, attention to detail, assurance of quality and its own category strategy. It requires the same intention that operators give to fuel, foodservice and inside sales, experts at The Car Wash Show agreed.