![[Laser cut and engrave] Engraving on copper sheets](https://image-res.xtool.com/ali-res/community/making/a77e8069-276d-4b82-b15e-f791af84b371/IMG_6518.jpeg?x-oss-process=image/resize,w_1200,h_900,limit_0/interlace,1/format,webp/auto-orient,1)
Sand well and degrease with a metal degreaser. I use the degreaser from sculpt Nouveau. Any grease from your fingers or other source will stop the laser from marking properly.
I have tried all the laser sprays and brilliance works best on copper. You can mark copper without spray, but you will be much better results with it.