clearing cache on squid proxy

 stop squid, and erase all the files from your cache directory 

For example:

squid -k shutdown

or

/etc/init.d/squid  stop

Find-out which is you squid cache Directory using following command

# more /etc/squid/squid.conf | grep ^cache_dir
cache_dir ufs /var/spool/squid 5120 16 256

  Here it is showing /var/spool/squid.

Then remove cache files ( Take a backup before deleting if required)

 rm -fr  /var/spool/squid/* 

 then re-create the swap directory structure:

squid -z

 now start squid again.

/etc/init.d/squid  start