I've personally been laundering my gold by using guild banks.
Take the gold, put it in a guild bank you have access to, and just take it out with your main.
What you could also do is just get the scammed gold, buy something on the AH with it, and then mail that thing to an alt you create on the scammed account. Then send the item(s) from the alt to your main. Delete the character that was sent, remake it, log in, log out and delete it again. The fact that it was sent to the same account is usually enough to cover you up.