Since Bill Clinton’s presidency, presidential challenge coins have become collectors’ items amongst a small, select group of campaign and administration staffers, diplomats, and members of the military. The coins are manufactured in small quantities to commemorate things like major trips taken by the president, and are handed out amongst other trip attendees, sometimes making their way to outside groups of collectors.

But Donald Trump, who’s never met a shiny gold item he didn’t like, has taken the coins to a new level, emblazoning them with campaign slogans and images that some have deemed controversial at best, and a violation of political ethics at worst.

On Sunday, The New York Times published a lengthy report about the challenge coins manufactured by the Trump administration, commemorating everything from Mar-a-Lago to his visit to the Vatican. The Mar-a-Lago one, in particular, has ethics groups concerned, citing federal laws that prohibit the use of public resources, like the taxpayer money that goes into funding the coins, to promote private businesses. Norman L. Eisen, chairman of watchdog group Citizens for Responsibility and Ethics in Washington, called it “a metallic tourist brochure.”

Another, which features Trump’s silhouette facing that of Kim Jong Un, made after the president’s historic meeting with North Korea’s leader, was criticized by Senator Chuck Schumer, who tweeted that Kim “is a brutal dictator and something like the Peace House would be much more appropriate.” The Kim design quickly became more popular amongst collectors than any other presidential challenge coin.

Trump’s challenge-coin designs have created a unique conundrum for an administration already under scrutiny for combining politics and business. One of the coins, paid for by the R.N.C. and approved by Trump, is “thicker, wider, and more gold” than the coins of preceding presidents, has Trump’s name on it three times, and replaces the traditional “E pluribus unum” national seal with Trump’s campaign slogan “Make America Great Again.” The White House Counsel’s Office has already warned staff not to display the coin in government buildings, and other ethics groups have said that the “MAGA” coins shouldn’t be distributed amongst the military, as politics and the military ought to be separated.