Your board looks like that because you used a brass brush after waxing. Brash brushes are meant for pulling up wax. It's what I use BEFORE I wax to pull up the old wax and get my base clean before using a base cleaner or going to waxing step.
I only use a scotchbrite Brillo pad after scraping and call it a day. On good conditions, I will use a nylon brush and the cork my base for the final polish.