Juilets that was a great story and very nice of you to make that man's day at no extra cost to you.
It reminds me of my younger days when I worked at a filling station after my day job and weekends. Many young girls and older women put on shows just as you wrote. Some even topless. I'd go home and tell my young bride.
The advantage to this was she thought those were great ideas and to this day still does the same. Even old tits and older pussy turns us old perverts on.
You asked for suggestions. I'd get that filthy car washed more often. In time I'd ask that attendant if he enjoys the little shows you put on. Maybe his assistant will help him wash your windows. Depending on his answers, you can show and do even more. If his answers are negative he's gay and you need a new car wash.