It isn't that easy. Anyone paying money for a homemade bar will test it first. The ancient gold will be very impure by bullion standards. The fact that it was horde gold will be found out very quickly.

>Anyone paying money for a homemade bar will test it first.

There's a pretty lively market in gold on ebay. Often forged into bars or coins by end users.

I have personally dealt with retail gold buyers who legally clear gold of all sorts with little question. They pay based on purity and likely have a price for whatever purity the horde gold is smelted at.

There's also that Singapore Gold Port at the Singapore Airport. Even if they wont touch you directly, there are IIRC, in person trades in the airport which can then be deposited straight into storage.