duckian on "[Plugin: W3 Total Cache] cannot delete 'cache' folder in wp-content"

Try out the plugin. Do not need it anymore, so I uninstalled it by:
- Deactivate plug in and Delete
- remove added lines (by plugin) from .htaccess at root, and wp-config.php
- remove w3tc related files and folder inside wp-content

But I cannot delete the 'cache' folder, which contains 'config' and 'page_enhanced'. FTP program gives me 550 errors.

Pleas help. Thanks.

http://wordpress.org/plugins/w3-total-cache/