Firstly you select the article you want to delete, then click on the 'Trash' button. If asked to confirm, click yes or OK.
The article is then placed in the trash, but NOT deleted.
The second stage is to select the article you just placed in the trash and click on the 'Empty Trash' button, again if asked to confirm, click OK or yes.
The following images show you the process.
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Be advised, after you have emptied the trash, you will NOT be able to retrieve the article in the future, it is gone for ever.