Backup and clean up

Hi,

My disk partition /var is full due to growing of postgresql DB.

I am using postgres DB for more than six months. After taking the backup I
have to clean up all the DBs.(drop data only.This means table,DB structure
must be maintained).Because, my data partition size is more that 90% in
use. For ex.

/dev/sda6 4.3G 4.1G 105M 98% /var
Eventually, no one db,tables structure should not be altered and it should
run without any issues.Please advice me on this.

or else how can i move this DB to some other partition. For ex : /data2 if
this possible, Please help me out.

Thanks in Advance.

Prabhakar.