OLD BROWSE INDEX PURGE
Check that you have a backup of the SQL database before doing any purging. You have been warned.
For DSpace =>5.X
A new command has been introduced with DSpace =>5.X.
See below for an example.
$HOME/bin/dspace index-db-browse -f -d
See step 11 of: https://wiki.duraspace.org/display/DSDOC5x/Upgrading+DSpace
For DSpace <=4.X
Step 1 - Remove "communities2item" table
Login into the server as the dspace user and then type the following;
su - postgres
DELETE from communities2item;
Step 2 - Remove all "bi_" tables
I used pgadmin to do a "cascade drop" of all the bi_* tables, where bi = browse index.