Are Tips Appropriate At a Car Wash?

After taking "newnew", my token Elantra over to Seattle this last weekend she was a little dirty-- and with the sunshine, it was just time to give her a bath.

So, I am sitting in the car wash staring off into space as the car wash ends I slowly drive through and am instructed to stop. As I do so, a teenage boy comes over and dries my car... I look over and the car next to me tips his car dryer-- was I supposed to tip this kiddo? Do these kids

I mean, I NEVER carry cash with me so even if you are supposed to I couldn't-- unless they want the countless pennies I have in the cup holder. I usually go to the unattended car washes, or just wash my car myself-- So what exactly is the appropriate thing to do at the car wash?