I got approached about the grocery store receipts also. Doing my due diligence. I went to the store, got a long receipt tape for my grocery purchase and called every business on the back of the tape and asked if they had seen any increase in business from it. Not one business said they were going to do it again. Everybody just throws them in the trash and never looks at them. I would also like to find something, but for now I'm stuck to banners outside the wash, facebook, and telling everyone I know about my car wash. I try to get my customer's to get the word out and I will treat them to a free wash once in a while.
Thanks,
Lighthouse.