I just did the logos on an old Leblanc and they came out perfect. I do have a recommendation however. DON'T use a needle or anything metal to clean the logos. You'll find it can create accidental scratching and actually deform the engraving. INSTEAD, use wooden toothpicks. The round ones NOT the flat ones. They work much better than needles, etc., and will not gouge the wood. Also I found it unnecessary to use heat of any kind. Just rub the crayon into the logo and carefully wipe the excess. Here's an example of how it looks on a Boosey....haven't taken pics of the Leblanc yet....