PHILADELPHIA (CBS) — A project is underway to help preserve and protect the outdoor statues at Independence National Historical Park.

Crews used a blow torch to heat the wax that they applied to the bronze statues of George Washington and John Barry.

Chief Curator Karie Deithorn says they’re working to wash and wax all eight statues at Independence Park.

“The John Barry statue here has a lot of pitting up on the top of his hat, where the metal is actually being eaten away by the elements,” she said. “So the way to prevent that is to keep them waxed.”

When the wax hardens, the statues are buffed to a shine.

Deithorn says they plan to do go through this preservation process every three to five years.