How to properly reduce oxidized gold?

I dissolved and precipitated gold in aqua regia. Then took the brown gold oxide to a blower. He used a kerosene gas with an oxygen air compressor. He added some borax. When it all melted the gold became now shiny black gold instead of yellow. I think the flame was too oxidized They normally use that blower to melt yellow gold dust. Didn't work for me. Is there another way like electrolysis or something or if I use now an acetlyne torch with a reducing flame am I going to get the same bad results???