I recently deleted the entire contents of my coppermine gallery (30,000+ images) and now I have thousands of albums I need to remove. I have been considering just removing the entire gallery and installing a new one because I can't figure out a way to delete more then a couple of galleries at a time.
It's probably the easiest way to just install a new gallery if you want to clear everything. The only way to batch delete the remaining albums is to do that with a appropriate query in the database (execute something like
DELETE FROM cpg15x_albums
in e.g. phpMyAdmin).