Before cleaning the mold, the product area should be clearly defined First, carefully grind the product surface area with coarse sandpaper Do not grind to the corner position of the product, otherwise, the cutting edge of the product in the later process will be inaccurate, resulting in the product size not standard After finishing grinding with coarse sandpaper, select fine sandpaper to polish according to the surface condition of the product until there is no landmark on the surface of the product After polishing, carefully check the edge of the mold. The edge should not be too sharp, otherwise, the vacuum bag will be cut when vacuuming later