Fences may help make good neighbors – but signs posted in store windows don’t always work.

Last month a business owner in Clifton, N.J., posted a hand-scrawled sign in his window reading, “Speak English or pay $10 extra.”

“When in Rome, do as the Romans do,” Dave Feinberg, owner of Cutters Edge, a knife-sharpening business, since 1995, told NJ.com.

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He soon found the knives were out for him: The backlash in the diverse community was swift and severe, the outlet reported. Many of the neighboring businesses are owned by Latinos or Middle Eastern immigrants, the report said.

Feinberg said he posted the sign after a frustrating encounter with a customer.

“Guy comes in with some product. Wants me to go over it. I have a hard time understanding him because he refused to speak English or make an attempt to speak English,” Feinberg told NJ.com.

“I was very frustrated. And the thing that frustrated me was making no attempt to speak English.”

He has since posted a new sign, reading: “Sorry about the speak English sign. Please except [sic] our heartfelt sadness it may have caused. [sic]”

But other business owners and shoppers had little sympathy for Feinberg, with some accusing him of racism, the report said.

“So there’s two types of racists,” Aseal Nassar, a frequent visitor to Clifton, told NJ.com. “There’s the type that are very firm in what they believe in and they don’t care and will tell you straight to your face: I don’t like you because you’re Spanish. I don’t like you because you’re a Muslim.

“And then there are the racists that once they get hit, they want to take it back and make excuses. And [Feinberg is] that type of person.”

Mohammad Mussalam, owner of a nearby hair salon, predicted that Feinberg may see repercussions from the sign showing up in his sales figures.

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“He’s going to lose a lot of customers,” Mussalam said through a translator, the report said. “It’s racist. It’s prejudice. It bothers me.”

With nearly 38 percent of Clifton’s residents identifying as Hispanic or Latino, and 35 percent of all its residents being foreign-born, according to U.S. Census figures, some suggested Feinberg picked the wrong location for setting an English-only policy.

“It was a stupid thing to do,” resident Michael Fazio told NJ.com. “And it’s going to cost him.”