Shawn Moebius puts beer in a keg at the Lakefront Brewery in Milwaukee. With metal prices rising, beer makers say they expect to lose hundreds of thousands of kegs and millions of dollars this year as those stainless steel holders of brew are stolen and sold for scrap.

Milwaukee ? Tap it, don’t scrap it.

With metal prices rising, beer makers say they expect to lose hundreds of thousands of kegs and millions of dollars this year as those stainless steel holders of brew are stolen and sold for scrap.

The beer industry is coupling with the scrap metal recycling industry to let metal buyers know they can’t accept kegs unless they’re sold by the breweries that own them. They’re also pushing for legislation that would require scrap metal recyclers to ask for identification and proof of ownership from would-be sellers.

The beer industry’s main trade group, the Beer Institute, noticed the problem in the past few years as it saw more brewers reporting missing kegs, resulting in an industrywide loss of up to $50 million a year, said Jeff Becker, president of the Beer Institute.

“It really got people’s attention because that’s a significant flow of our kegs that we’ll never see again,” Becker said. “We know some of it’s very innocent but some of it’s not.”

The theft problem is twofold, he said. Some average keg-buying customers opt to forgo their deposits, which sometimes can range from $10 to $30, because they can cover that expense, and then some, if they sell to scrap dealers.

He could not say how much kegs go for, because prices change locally. In the past year, a keg could fetch from $15 to $55 or more at scrap yards.

But he said thieves know metal prices are on the rise and are on the prowl for kegs.

While only about 12 percent of the nation’s beer is sold in kegs each year, it costs brewers as much as $150 to replace each keg, so the thefts have a big impact. In the past few years, breweries have collectively lost about 300,000 kegs a year, Becker said, out of an estimated 10.7 million in circulation.

The Fourth of July is the nation’s biggest beer-drinking holiday, the Beer Institute reports.

Free State Brewing Co., 636 Mass., and 23rd Street Brewery, 3512 Clinton Parkway, have lost a small number of kegs through theft. Each business charges a $100 deposit to customers buying a party-sized amount of beer in a keg.

“We’re lucky that we’ve suffered very few losses,” said Chuck Magerl, proprietor of Free State, which sells about one-third of its beer through kegs. He agreed that keg thefts are a significant concern across the country.

“Kegs are not just waste that someone has picked up along the roadside,” he said. “They’re the property of breweries. It’s no different than selling property you’ve pulled off a truck somewhere. It’s a theft issue.”

The Cork and Barrel store at 901 Mass, which charges a $60 deposit, doesn’t have a theft problem with kegs, said manager Larry Johnson.