But you can use a swab or cloth to clean the outer part of the ear.

VOA: special.2010.03.31

You cannot just tell the computer to enhance that or can you clean that up and then magically use zoom in not only on the image but also on the reflection of the victim in someone's eyeball.

你不能直接要求计算机增强,这张图片或者修复它,然后期待计算机很神奇地放大图片,以及死者的眼珠的反光。

哈佛公开课 - 计算机科学课程节选

They then use the toilet to clean the flag.

然后他们就用马桶来弄干净国旗。

耶鲁公开课 - 心理学导论课程节选

If you cannot find anything clean, use your hand.

VOA: special.2009.08.11

"We say,find more American energy and use less--energy that is as clean as possible, as reliable as possible, and at as low a cost as possible.

VOA: standard.2009.04.25