Company owner Jonathan Appell is mentioned in this article for the advice he gave to use D/2 to clean the two iconic statues in Freeport, Illinois.

http://www.journalstandard.com/news/20161010/freeports-former-carnegie-library-statues-get-facelift

FREEPORT — In the next week or so, passersby should notice the two statues sitting south of the former Carnegie Library look much cleaner.

The statues, which are part of a set representing the four seasons that Freeport industrialist W.T. Rawleigh bought in 1931, aren’t covered with dirt and marred by pit-like indentations, as some residents think, said Jessica Modica, executive director of the Freeport Art Museum.

Rather, a lichen is growing on the Carrera marble and can be killed with a biological solution, said Sharon Welton, executive director of the Stephenson County Historical Society. Modica and Welton removed what lichen would easily fall off with brushes on Friday and then applied the solution. They plan to return to brush off the dead lichen and spray down the statues again, if needed.

Their efforts dovetail city officials’ plans to finish renovating the former library at 314 W. Stephenson St. into a new City Hall so the offices can open in January.

“I’m glad the city has decided to keep them here,” Modica said. “They are iconic to Freeport.”

Welton’s friend, Jonathan Appell, who conserves monuments and headstones, examined the two statues in early June and donated the biological solution to their efforts. Overall, they are in great condition for their age, but restoring the glaze that once covered them would be expensive, Welton said.

She suggests adding gravel or other landscaping around the concrete bases to avoid grass trimmers getting too close to the two statues.

They were made by Italian sculptor Ferdinand Vichi. Two statues from the set, Spring and Summer, are at the Freeport Art Museum, 121 N. Harlem Ave., so the statues outside the Carnegie Library are likely Autumn and Winter, although they are not labeled.

A receipt in the historical society archives indicates Rawleigh paid $471.73 for the set in 1931. According to two inflation calculators, that would be between $6900 and $7400 in today’s dollars.