Too gentle a rubdown leaves contaminants on the surface . Too vigorous a scrubbing erodes the metal itself .
擦拭太过温柔,其表面会留有污染物;用力过猛,又会擦掉金属本身的表面成分。
In addition the beforehand media once reported that the oversized student scratches the leather shoes , to give somebody a rubdown , manicure and so on , can not but say , present 's university students indeed were " the high quality common laborer " .