I had similar trouble with a double I rust blued. I submerged it in gasoline for a day or two, then cleaned it with paint thinner and then acetone. Mine had the weep holes described and the last two cleaning soloutions were poured generously in the hole. After this treatment the bleed through stopped. I was glad it did because of the hassle to get it removed and relayed back on just didn't seem worth it for two little tiny unseen holes.