Before any engraving, please make sure to clean your tin box with rubbing alcohol in order to avoid and greasy marks. This way, you will make sure your surface is clean and ready to be engraved. Then make sure that the laser is properly levelled. You cannot believe how many times I have forgotten about this step and ended up with a blurry engraving. I always use 100% power and around 200 to 300 speed. If the engraving is not clear enough you can always add a second pass. Engravings take very little time. This one takes under a minute so this is perfect for batch orders. You can always add a few boxes on your base plate and engrave four or five at the same time.