@physicsnico@GiftedTawk Typically I just lightly sand to remove any brown soot from the surfaces. I would not apply oil to an engraving as the contrast will go away. You can use a water based poly acrylic to seal the ornaments with very little loss of contrast.
STEM Teachers: What is the process for finishing a laser engraved wooden ornament? Do I wash in water, followed by mineral oil and board butter? I’d appreciate your expertise. Thanks.