Hong Kong customs officers have discovered HK$230 million (US$29.4 million) worth of gold and silver hidden in two air cargo shipments of household cleaning machines destined for Japan, making the largest seizure of precious metals on record.Senior Investigator Ho Ting-chun of the Customs and Excise Department’s syndicate crimes investigation bureau said on Thursday officers intercepted 168kg (370lbs) of suspected gold foil and 285kg of suspected silver foil worth HK$230 million in an operation...