1, the first  shell phone with a wet cloth to clean under the dust. 
2, there are cracks in the metal shell phone dust can be added with a toothbrush to clean with soap, metal shell phone easily washed off the dust, so do not use too much effort to brush, just gently brush again, we can achieve the desired effect. 
3, if there is a particularly strong sticky and very stubborn stains, you can use alcohol or a cleaning agent, alcohol, and cleaning agents for paints, pigments, paints and building materials have a better cleaning effect. Unlike alcohol, it is not easy to burn cleaner, colorless and tasteless, more at ease with them. 
4, if there is rust then proposed using 2% of the acid solvent and dissolved grass, spray rust places, over 2-3 minutes with a paper towel or cloth to wipe it clean. 
5, the last phone with a dry cloth and liquid water stains on the shell clean.

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