black lion on "[Plugin: W3 Total Cache] how to delete rest files"

I had used the W3 TC but after a crash I see that the whole plugin of is gone. No problem. But on the server are a lot of files that I have to remove but they can't be removed. How to manually remove them. The server uses a plesk desktop. Help me out to get rid of those files.

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