It turns out the course of muriatic acid and bleach applied by city workers can eat away at the soft marble stones.
Most experts recommend, instead, plain water and, if absolutely necessary, diluted ammonia or a non-ionic detergent applied with a soft brush and heavily rinsed.
“Absolutely no acid product,” said Mike Loflin of the Marble Institute of America. “It’s cleaning the grime ... but it’s also removing calcium minerals.”
For the past two weeks, city workers have scrubbed dozens of old marble headstones in the cemetery as part of Mayor Bill Williams’ push to spruce up the grounds. The city has spent tens of thousands of dollars in recent years to add parking, replace old fences and build a new stone entrance.
The headstones were the most recent part of that overall plan, and the process has returned the markers to their original white surface, making names and dates legible again.
But Guntown resident Lynn Wesson said she’s furious about it. Several members of Wesson’s family are buried in the cemetery, and she said the city is ruining their headstones with its cleaning process.
“I’m going to mark every last one of them, and I never want them to touch any of them again,” she said of the stones. “They are not supposed to be gleaming white after 100 years.”
When contacted about the complaint and expert information, Williams told the Daily Journal that muriatic acid is a common cleaning solution for stones and that the process didn’t hurt the ones in the cemetery.
He also said the city published a notice at the launch of its cemetery renovation project inviting residents to voice their concerns, but no one did. Wesson said the notice never mentioned muriatic acid and bleach.
“When the acid was on the stone, most of it was working on the grime and debris, not the stone itself. And it was thoroughly rinsed away,” Williams said. “In my view, it was successful.”
The mayor said he has heard mostly positive remarks from residents about the effort.
Muriatic acid is a common masonry cleaner, Loflin said, but shouldn’t be used on marble because of its soft, porous nature.
Now that the city has finished its cleaning, Williams said it will maintain the headstones twice annually by spraying them with diluted bleach. But the International Association of Cemetery Preservationists recommends cleaning them just once every 10 years, and it frowns upon bleach.