More of a trick than a true exploit. The idea is to buy a Goldskin armor which gives you a chance on hit for the monster to drop gold. Then, combine the armor with LOW dps weapons (preferably with life on hit) and spec for whirlwind. Make sure you have a decent amount of pickup radius on your gear. Go find a giant pack of weak mobs (demon imps at the beginning of Stonefort or groups of scorpions in Act 3 work well). Now go crazy whirlwinding your heart out and collecting the piles of gold that drop.
With low dps and high LOH, you won't kill the monsters very fast but you also won't die. Your Goldskin armor will proc all day and with enough pickup radius you shouldn't have to ever stop looting piles of gold.