From Nagano Skate exclusive diamond sheets, those Frank's Signature burr stones are very efficient and always clean. Only use a dry cloth to clean them, no oil, no water.
Uses of every grit:
When choosing your options, note that larger the number in parentheses next to the color is, softer the stone is. The black is therefore rougher and the gold softer.
Black (140): To fix dammaged or wavee blade.
Blue (400): For strips. Gross burr, 1st step of polishing a new blade.
Red (600): De-burring after sharpening, 2nd step of polishing a new blade.
Gold (1200): De-burring and Polishing