If you have uploaded the files individually by ftp or something similar, you can simply delete files.
If you have used the installation script, there is a bit more to do.
<?php unlink ('brim'); ?>
Now delete the brim database (execute something like 'drop database brim' using the commandline, phpMySQL, a similar tool) or delete all tables with the following prefix 'brim_', if the application is installed in a database shared with other applications