As patients at a Vancouver, Wash., free clinic wait for medical and dental appointments, they have the opportunity to thank the donors who helped provide those services.

Several patients each week fill out thank-you notes left in the waiting room of the Free Clinic of Southwest Washington, though no one at the clinic directly asks them to.

Some of those notes are then photocopied and sent with formal letters from the charity thanking donors for their gifts.

Haley Overton, the clinic’s communications and marketing coordinator, says she sends a copy of each letter to only five to 10 donors. That keeps the letters fresh, she said. (An excerpt of one note is included below.)

Ms. Overton also updates that formal letter monthly with new statistics about the number of people served, both to be accountable to donors about where their money goes and to show them how the need for services continues.

“We are really proud of the patient visits we perform each month,” she said. “Our service is very needed in our community, so whenever we send a letter to donors, we want to show them hard facts of what their donation is providing.”

Ms. Overton begins her letters by talking about the state of health care in the area. The clinic says 60 percent of its patients report that they wouldn’t receive medical services if they weren’t available free.

“We have people who have full- or part-time jobs, but they just don’t have insurance,” Ms. Overton said.

This letter is part of the Great Acknowledgment Swap, a collection of letters gathered by Lynne Wester, director of stewardship and donor recognition at Yeshiva University and blogger at donorrelationsguru.com. You can see the full collection of more than 600 pages on her site.

As always, we invite you to critique the letters and borrow ideas for your own acknowledgments.