The FBI is warning of a currency scam that might target wealthy Asia-Pacific Economic Cooperation delegates.

In the scam, construction paper is passed off as U.S. money that has been dyed black so it could be smuggled into the country without alerting U.S. Customs.

The con men persuade the victim that the dye can be removed, and ask for money to buy necessary chemicals, according to the FBI. In exchange, the victim is offered some of the black money.

The swindlers then disappear with the real money.

On Friday the proprietor of a Honolulu self-storage company contacted the FBI after two men, who identified themselves as Liberian, rented a small storage locker for cash Oct. 11 for a month, said FBI Special Agent Tom Simon.

Inside, they placed only two black suitcases.

The Police and Fire departments checked the storage locker Saturday and, without opening the suitcases, detected no explosives or dangerous materials, Simon said.

After obtaining a search warrant Saturday night, the FBI opened the suitcases and discovered 120 pounds of black construction paper cut to the size of U.S. bills and shrink-wrapped. White glue, iodine, empty glass vials, a hair dryer and vitamin C powder — materials needed for the scheme — were also in the suitcases, Simon said.

The men might be in Hawaii targeting wealthy foreign officials and corporate executives here for APEC meetings, Simon said.

The FBI is urging people who may have been defrauded to come forward to help "put these guys behind bars," Simon said.

THE Associated Press reported that the scam recently hit New England states, where three people lost $170,000, according to the Secret Service.

In Rhode Island the Secret Service arrested two Liberian nationals who allegedly attempted to deceive an undercover agent. (The FBI in Hawaii is stepping in for the Secret Service, which normally handles such crimes but is occupied with APEC matters.)

As part of the scam, the swindlers demonstrate the dye-removal process.

They dye a $100 bill black using iodine over a protective layer of glue. Then they show how the dye can be washed off with a special chemical, in reality a mixture of vitamin C powder and water.

The suspects in New England asked the victims for money to buy the chemical in exchange for half the dyed money, saying they were forced from their country and cannot afford the chemicals in large enough quantities.

Some use email to ensnare victims, but others, such as in the New England cases, go to nightclubs or restaurants, targeting potential victims who are wearing expensive jewelry or driving luxury cars.

Simon said the scam has been promoted over the years by Nigerians, Ghanaians and Liberians.

Although the FBI could try to track down the suspects, "preventing the fraud from occurring is a better use of resources," Simon said.

Anyone who may have been a victim or who has information about the two men who are wanted for questioning should call the FBI at 566-4300.

The Associated Press contributed to this article.

Hawaii News Now video: FBI warns of ‘Black Money Scam’ in Hawaii