Aluminum is a material Really beautiful, but its characteristic gray color makes it stain with certain frequency and that maintenance at the cleaning level is highly recommended at least a couple of times a month, or even once a week.
For very little money
If cleaning it doesn't look like if it is very hard (that is, it is not very dirty) the best option is to use an alcohol slightly moistened with water or moistened wipes sold in large stores. When we see that it is clean we simply have to dry with a clean cloth and the Mac will look like jets of gold.
In the event that we see that a deeper cleaning We can choose isopropyl alcohol (if we have it, because it is less aggressive) or the alcohol "to cure" of all life, ethyl. Both options are valid and will make the spots that seemed not to come out disappear with some effort, but much less than if we did not use it. After applying it and leaving the surface perfectly clean, you have to wipe it with a totally dry cloth and leave the Mac pristine for use.
Obviously this same technique It can be used for keyboards, the mouse (in fact alcohol works better on glass and plastic) or the accessories that we have accompanying the Mac at home. For example, I always include the Elevation Dock and the Magic Charger in my weekly cleaning routine.
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Note: There are many specific products for aluminum and Mac cleaning. I have simply described a method that works and with material that we all have at home.
Be careful !!!… Alcohol tends to wash away the paint from the screen printing on keyboards and other parts of the equipment. I would not take this advice. A clean and damp cloth is enough ...