Millstone, sandpaper, nail file, granite surface, concrete walls and floors above all contains material, will be scratched surface of these materials.

磨石、砂纸、指甲锉、花岗石面、混凝土墙面及地面等均含有以上物质，会刮花这些材料的表面。

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First of all, to deal with some spraying petrol, acetone for degreasing treatment with a file, fine sandpaper, oilstone will fatigue layer and oxide layer removed to expose the metal color.

首先应对喷涂部分用汽油、丙酮进行除油处理，用锉刀、细砂纸、油石将疲劳层和氧化层除掉，使其露出金属本色。

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