When communicating in Chinese you may often make mistakes using Chinese grammar like:

False:

    他的房间收拾得干干净净极了

    Tā de fánɡjiān shōushi dé ɡānɡān jìnɡjìnɡ jíle

True:

    他的房间收拾得干干净净。

    Tā de fánɡjiān shōushi dé ɡānɡān jìnɡjìnɡ.

重叠形式的“干干净净”用作程度补语时，它的后面不能再跟表示程度的词语，去掉“极了”。

When the reduplicative form of an adjective such as 干干净净 is used as a degree complement, it can not be followed by other words indicating degree. 极了 must be deleted.