How to clear the cache

Hi 

      Just a query though it is very basic question ,
but as i am very new to bind , so i need to know..

      Recently one of our server's ip address has been
changed. So for that we have replaced all the old ip
address with the new one in the DNS. We have 2 own
domain name servers assiged to two cobalt servers with
bind 8.2.3 version. the changed
ip server has also a zone in these servers. 
      Now if i restart these two servers - does the
cache will be cleard? 
      Please guide me....

Thanks in advance.
-Swapna

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