सुनिश्चित करे कि पश्च आवरण की मुहर भीगी हुई न हों

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Note added at 4 hrs (2006-07-22 07:12:13 GMT)
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If you add अवरोधक मुहर/सुस्थित मुहर for seal then it will be nearer to your context as
-सुनिश्चित करे कि पश्च आवरण की अवरोधक मुहर भीगी हुई न हों/
-सुनिश्चित करे कि पश्च आवरण की सुस्थित मुहर भीगी हुई न हों/
otherwise transliteration सील is also very common

Seal has many meanings in Hindi. We should choice according to context. Seal has also a meaning 'To hold tightly'.
Ex: The envelop is not properly sealed.
लिफ़ाफ़ा सही तरीके से बन्द नहीं हुआ है

'Seal' can be used as noun, verb or adjective.



In this case,'Seal' is used as noun।
In my poinion, the word will be:

निश्चित हों कि पृष्ठ आवरण का बन्धन भीगा नहीं है

Here seal refers to the connecting area. This would also be a right answer in given context.