1.) put all your blacklist emails into a text file called black.csv, one on each line.
2.) upload to database server, put in root directory / (if you have database and web server on the same machine then upload to 'server' in the / directory)
3.) in phpmyadmin
LOAD DATA INFILE '/tmp/eml_blk.csv'
INTO TABLE `mw_email_blacklist`
FIELDS TERMINATED BY ','
OPTIONALLY ENCLOSED BY '"'
LINES TERMINATED BY '\n'
SET reason = 'Hard Bounce', date_added = now(), last_updated = now();
Instead of taking an eternity to upload you bounces they all go in quickly.