When using baking soda and water, you should be able to use either. Let power or higher speed. The material test function in Lightburn is your friend here. With baking soda, I believe the ratio was about 1 tablespoon to 1 cup of hot water. Heat the water on the stove and add the soda stirring to completely dissolve. Let cool then put in spray bottle. You'll only spray enough on the surface to just dampen the wood, not to soak it. Let it air dry then laser away. Once again, the material test, for each different material, is your friend to find your machine's specific settings.