I am currently finishing several turned boxes made of lignum. After sanding, I seal  with 2 coats of Liberon lathe polish which is, I believe a shellac based formula, and then buff and finally coat with paste wax (and buff again). Sometimes this works and sometimes I get green bands reappearing through the finish. Is there a definitive way to seal lignum to keep blotches of green from popping out through the final coat of wax?