MY GRADING IS BASED ON OVERSTREET'S. (Following is a summary of his grading guide).
7.0 FN/VF Minor wear, small accumulation of bindery/printing defects allowed. Minor cover wear and minor creases allowed. Corners may be blunted. Staples may show some discoloration. Staple tears and stress lines may be present. Minor interior tears at margin allowed. Paper is cream to tan
8.0 VF A limited accumulation of bindery/printing defects allowed. Cover flat with minimal surface wear, including wear at corners. A 1cm crease is acceptable if colour is not broken. Staples may be discoloured. Very slight staple tears and a few minor stress lines may be present. Paper is cream to tan.
9.0 VF/NM Cover is flat with almost imperctible wear. A 5 mm bend allowed if colour not broken. Corners are cut square with ever so slight blunting permitted but no creases. Staples may be discoloured. Slight staple tears allowed. Small accumulation of stress marks may be present as well as very minor interior tears. Paper off white to cream.
9.2 NM- Cover flat with no surface wear. A limited number of bindery/printing defects allowed. Corners square and sharp with ever so slight blunting permitted. Staples may show some discoloration. Almost no stress marks. Paper off-white to cream. Slight interior tears allowed.
9.4 NM Only minor imperfections allowed. Subtle bindery/printing defects. Small tears less than 5mm. Cover has no surface wear. Ever so slight blunting of corners allowed. Staples are generally centred and may have slight discoloration. Almost no stress lines. Paper off-white to cream. Minor interior tears allowed.
9.6 NM+ Only subtle defects allowed. No bindery tears allowed. 1 corner may be almost imperceptibly blunted. No crease, bends or color breaks. Staples show only slight discoloration. Paper is off-white. Only the slightest interior tears may be present