Easy Off is your solution. Depending on part surface area and shape will determine soaking time. If doing indoors at ambient temps (21C/70F) and as a reference, I have found that Ringle holeys can take about an hour to penetrate ano in fairly good condition. After soaking, rinse with warm water and use a wool brush to clear any residual color. I'm not a metallurgist, but the acidic cleaner can probably weaken the metal so I would be conscious of over exposing the parts.