Always keeping us on our toes Karen
Pencil marks have been a nightmare in the decorative concrete industry since it began. Framers, HVAC, fire sprinkler pipers…just about any and all trades that see a nice clean slab of concrete seem to want to leave their mark. Pencil, red chalk lines (love it when they spray lacquer on the line to preserve it) and spray paint. I have seen jobs (all from your crazy state) where folks just sealed the bare concrete with all the “artwork”, they say they like the industrial look, I think they just couldn’t get it clean.
Sanding is the only surefire way to remove pencil every time.
Eraser (use duct tape first to remove excess to prevent spreading. They have clear duct tape now, does not matter, but cool none the less)
Hair Spray (spray and scrub with water-hair spray sticks to the pencil and gums up when hit with water)
Acid (if possible)
Ammonia & Peroxide (soak with ammonia then hit with a few drops of peroxide)
Poultice with neutral cleaner
Metallic marks? When you can use it, a little acid usually does just fine, along with a green/red/white pad.
Hey Andy, how about a cool laser guide on a Felker, just like them newer mitre saws?