I have two washes. The older wash has no way to give a code for a free wash. When my machine eats their 4 quarters because of a malfunction, I offer a refund, but sending out a check for $1 or $2 seems ridiculous. Many times I let them know what hours I will be there so they can get refunded in person. Not sure if there is way to handle this efficiently and still make the customer happy. I was curious what other unattended self-serve operators do in this case.