Hello all, great forum with lots of great information. I am new to the woodworking side of engraving and have a question about sealed wood. I have a Universal laser and need to engrave a plaque that has been stained and sealed with Minwax Polycrylic. Is this safe for the machine? I know there are some things that can damage the lens and I just want to make sure I am not causing any problems. Thanks for the help.