How to restart Squid with a clean cache
First of all, you must stop Squid of course. You can use the command: 
	squid -k shutdown

The fastest way to restart with an entirely clean cache is to over write the swap.state file. Note, you can not just remove the swap.state file, or truncate it to zero size. Instead, you should put just one byte of garbage there. For example:

	echo "" > /var/spool/squid/swap.state

Restart squid:

	squid