This is the following criteria I use to quality check my items. Please note, there may be other unlisted things that classify a pin as the grade they are listed as.
Please note : Enamel pins are handmade items, as such they can contain minor flaws from the production process.
A grade/Standard grade pins :They may have some slightly noticeable specks, defects and or scratches when tilted, but are not noticeable when on display. Standard grade pins may be free of flaws or have minor ones. Some of these minor defects Include (but are not limited to) some light imperfections in the metal plating , light surface scuffing on the enamel or metal, light or very small nicks on the enamel or metal.
B grade pins : B grade pins have noticeable flaws throughout the pin such : as noticeable or multiple areas of under filled enamel, moderately scuffed enamel or metal, multiple points of imperfections on the metal plating, unfilled areas of enamel, multiple air bubbles in the enamel, missing metal lines, missing enamel, off-set screenprinted areas, overfill on the enamel and more.
C grade pins : C grade pins have VERY MAJOR scruffs . They may have the following : large and very noticeable areas of scuffing. large or deep gouges in enamel . large areas of under filled enamel. multiple defects or imperfections in the metal plating. large and multiple air bubbles in enamel. multiple areas where glitter has been misapplied . large or multiple areas of missing metal lines.multiple areas of enamel staining or discolored enamel. significant areas of low-fill. more than one unfilled enamel area. areas where enamel is missing and more.