I have lots of Pierco foundation that I am going to recycle and use again. They are old dark comb, wax moth and SHB damage. What is the best way to clean it and how clean is clean? I started out by scraping off all the old wax with a putty knife and then a light brushing with a cup brush on my 4" angle grinder. There are still lots of dark spots from the bottoms of the cells. Do I need to remove all of this before rewaxing?