Delete unused product such as disabled products, products without image etc.
You can simply run next command which delete all disabled product, product without images and permanent rewrites from core_url_rewrites
php shell/deleter.php --delete all
Also you can run all command separately
php shell/deleter.php --delete disabled
php shell/deleter.php --delete noImage
php shell/deleter.php --delete rewritePermanent
php shell/deleter.php --delete rewrite