"Brushless" carries the clearest intent of any search here. It comes from somebody with a new or dark car, it has little competition, and it pays better than the standard wash.
Interior cleaning is searched completely separately and averages double the ticket. On most sites it still appears as one bullet in a list.
Weather drives the demand, but the calendar can be prepared for. After the winter salt and before the spring holidays there are two reliable waves; having the pages ready beforehand is how you take them.
The monthly pass deserves a page of its own. It's what turns a business at the mercy of the forecast into one with predictable revenue, and it's searched by people specifically looking for one.