Hi @Wildwoodwaltz, my apologies for the poor experience so far with the marks that you are seeing on the screen of the device. We have seen rare instances where the protective sticker over the Leap Motion Controller's IR window leaves a hard residue that can look like a smudge or mark. This can normally be easily cleaned off with a microfibre cloth and a solvent (eg isopropyl alcohol, nailpolish remover etc). Would you mind trying that first and confirming if this resolves the issue?
If not, we'll gladly get this unit back and issue a replacement. Please can you send me a copy of your order confirmation to firstname.lastname@example.org and I will be happy to help you further with this.