The background should be white and the color of clothing must be clearly distinguishable from the background color. The photograph must be free from stains.

背景色为白色，衣服颜色必须和背景颜色有明显区别，照片无污点；

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You can't physically remove all the stains from floorboards so they clean it as best the can and paint a sealant on the top.

你不可能完全清除地上的污迹，所以他们尽量洗干净，然后在表面漆上一层密封剂。

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Mix 3 tsp with hot water to soak and remove tea and coffee stains from thermos’ and tea cups.

热水里加三勺小苏打可以溶解掉咖啡壶和茶杯上附着的顽渍。

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Those entirely righteous charges, you recall, to defend his reputation and honour from the stains being flung at it.

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The walnut top of his colonial style desk was marred by water stains from a second-story flood the office suffered months earlier.

FORBES: Magazine Article

Historically, nightingale bird droppings were used to remove stains from delicate silk garments in Japan, as well as by geishas to whiten and even skin marred by frequent and heavy use of makeup, Pacheco says.

CNN: Try a placenta or bird poop facial