if the substrate is metal, i sand blast it when possible or use 80 grit emery paper as a second choice.
如果基板是金属,如可能我就喷砂或者,作为第二选择80粒度的金刚砂纸。
the emery paper is applicable in the grinding and polishing of most work pieces including metal, metal alloy, ceramic, optical element, fiber connecter, hard disc and semiconductor, etc.