I don't know if this will work but it's worth a try.
Log onto the scammed account, press enter, and do /2. "Giving away free gold" Give people 3-4 gold each. Once you give about 5 people gold, open a new WoW Window, log onto your main, run up to the scammed account, and trade him the remaining gold.
Not sure if this will work but I saw it posted a long time ago for gold laundering.