I purchased this laser, a short while ago(3weeks). Looked at about 25-30 Tutorials,and tried to do about 20 different things. But most weren’t engraving well. Someone suggest not,using air assist during engraving. Tried doing a photo on basswood,engraving a map of Italy,which turned out ok after 4 try’s. Then after all those projects, it wasn’t functioning! The laser became,weak. So i looked up how to clean a lens and cleaned it throughly. I noticed that the lens wasn’t clear, like a round circle almost like an eyeball, lol!! My question is, did i damage that lens or is it still useable. I did recieve another lens,in my package, if needed? Also is there any chart to go by for settings on like, power,speed, lines per cm??? For engraving on wood, ceramic,or tumblers?? Any help would be greatly appreciated,and i,thank you in advance.  MIKE