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Bar Pilar bar manager Jonathan Fain is sick and tired of watching his copper mugs walk out the door. Of the 100 or so mugs that the bar uses to serve Moscow Mules, Fain says all but five have been lifted by sticky-fingered customers.

Fain offers a simple explanation for the mugs’ appeal: “If it looks good, people take them.” A service industry veteran who’s worked at Café Saint-Ex, 18th Street Lounge, and The Wonderland Ballroom, he’s watched customers help themselves to everything from St. Germaine spoons to special pint glasses. Someone even smashed a glass frame in the Saint-Ex men’s room to get to the poster underneath it. But, as has been previously documented in Eater’s “Shit People Steal” feature, Bar Pilar’s copper mugs seem to have a particular draw for thieves. As of this week, the bar was literally down to its very last cup, though on Wednesday Fain found four more hiding in a closet.

The rampant plundering of his copper mugs has Fain thinking outside the box to keep them safe.

“I tell the serves to keep a close eye,” he says, a strategy that was occasionally effective. “We’ve definitely had servers see people put them in their purses.” When caught red-handed with a Moscow Mule cup in their bag, embarrassed customers “are generally apologetic.”

“These are normal people who work on the Hill, work for senators and things like that,” Fain says. “To them, they don’t think anything of it. They think that a glass costs a dollar.” What they don’t realize, he says, is that they could be arrested for petty theft.

Calling the cops is not off the table for Fain anymore when it comes to protecting his copper mugs.

“I’ve definitely thought about it,” he says. “It’s been on my mind. It’s almost like there needs to be an example made.”

A call to police, though, would pull Fain away from what he says is his most important job: overseeing service. “To call the police to come out, it would take a half hour to 45 minutes of my time,” he says.

Fain has also considered requiring a deposit for a mug. A customer would have to plunk down a refundable $25 to get his or her Moscow Mule in the copper cup. Should the cup disappear, so would the customer’s cash.

“That would definitely discourage [stealing],” Fain says. “But I also don’t want to seem cheap.”

Another idea, to devise a device that would somehow handcuff the cups to the table, is unlikely to come to fruition because “that would be super terrible.”

Technically, the loss of the mugs isn’t costing the bar money. Fain gets them as part of a deal with his vodka distributor. But at a retail price of about $25, Fain can’t afford to restock the stolen ones. He’s already losing time and money on the disappearance of Bar Pilar’s Coke bottle glasses, which Fain hand-crafts. (Amazingly, Fain once got a phone call from a bride who received four of the glasses as a wedding gift. She recognized them from Bar Pilar and offered to return them. Fain graciously declined.)

The loss of the mugs is more atmospheric than financial. “People come in and say, ‘Do you have the copper mugs?'” he says. When folks help themselves to the cups, he adds, “You ruin the experience for everyone else.”