For the privilege of wearing jeans and other casual attire, employees donate $3, with the money going to a designated nonprofit organization.
While casual Fridays are now the norm throughout the workplace, few are so closely linked to philanthropy and fewer yet are done on such a comprehensive scale.
"I have never heard of that," said Karen Simmons, a veteran fund-raiser and president of the Chester County Community Foundation. "I think that's a wonderful idea."
Friday's dress-down day benefitted a childhood-cancer research fund at Children's Hospital of Philadelphia, a cause close to Hanna's heart and one that he asked to be added to the dress-down program.
Six years ago, his teenage son, also named Colin, was diagnosed with a brain tumor. The pediatric neurosurgeon who operated on him, Leslie Sutton, receives money from the fund for his research activities, Hanna said.
"The county's dress-down contributions to this fund have been around $1,000 a year," Hanna said. "That means over 300 county employees have chosen to support this charity, and I'm grateful to them."
His son, who recently graduated from Wheaton College in Illinois, has made a complete recovery, he said.
Last month, dress-down day turned the courthouse into a merry menagerie as Jade, a mixed-breed dog; Patches, a dalmatian; a lop-eared rabbit named Corrie; and three cats arrived from the Chester County SPCA to show their appreciation.
"These things are really important to us in terms of fund-raising," the agency's spokesman, Chuck McDevitt, said. "I thought it was really a nice thing to do."
The fund-raising idea was born more than 10 years ago when former county spokeswoman Joan Pitt enlisted county workers in a Blue Jeans for Babies campaign, a fund-raiser for the March of Dimes.
"That was sort of a test," chief clerk Nancy Seltzer said. "It sort of grew from there."
A list of groups chosen for the year and their dress-down dates are published the first of the year in the employee newsletter, she said.
In addition to the county's SPCA and the cancer-research fund, other charities on the list this year are the West Chester Community Center, the Domestic Violence Center, Wings for Success, the Police Athletic League, Canine Partners for Life, Toys for Tots, Community Volunteers in Medicine, and the one that started it all - Blue Jeans for Babies.
"The organization has to have a local connection for us to consider it," Seltzer said. "The day spreads money to organizations that maybe don't get a lot of funding."
In a separate charitable effort, the last Friday of each month is dedicated to Chester County Cares, an organization that provides a safety net of resources for people in need. But instead of money, employees are asked to donate personal-care items that are distributed to food cupboards throughout the county.
"It's another way of having our employees involved in their community," Seltzer said.
Guidelines for Dress Down Friday are few, but employees are asked to exercise a little bit of discretion when they are deciding what to wear, she said.
"These are public buildings, and we don't want the public to perceive the employees as just coming out of the garden or spending a day at the beach," she said.
Neat, clean, blue jeans that do not have holes, stains or patches are OK, Seltzer said, but spandex bike shorts are off-limits.
At the prothonotary's office, where civil cases are kept, Becky Lilley, 23, of Avondale, was wearing blue jeans and a medium-blue, long-sleeved cotton, knit shirt as she docketed a constant stream of case filings.
And on her shirt was a sticker that said she was a Dress Down Day donor.
"It's my way of giving back," said Lilley, who is the office representative for Dress Down Day. "This month is for cancer. Last month it was the SPCA."
Seltzer said employees such as Lilley have made the program a success.
"I can honestly say they have accepted this program with a lot of enthusiasm," she said. "It's an interesting way for them to contribute."
Contact staff writer Nancy Petersen at 610-701-7602 or firstname.lastname@example.org.