To clear download items in the Downloads panel, you can simply right-click and select Clear List, but to remove the items from the history, you have to open the Library and click the Clear Downloads button.
Depending on how often you clear download history, this standard method may become a hassle, especially if you want to delete it right away after finish downloading.
This is where these extensions come pretty handy.
This restartless add-on was made for one thing, to delete download history automatically. Each of your downloaded files will be gone from the history in five seconds after the download is completed or cancelled. Too quick? You can adjust the delay.
Note that if you set a fairly long delay, make sure to enable the option to clear download history on exit to so that there will be nothing left when you close the browser. If there is anything left, then you have to remove it manually as the add-on doesn’t delete download history from previous browsing sessions.
Version reviewed: Download Cleaner 22.214.171.124 on Firefox 39 and 43.0.4.
MODERN DOWNLOAD MANAGER
Unlike Download Cleaner where the auto cleaning is applied to every single item you’ve downloaded, Modern Download Manager allows you to choose certain files only by specifying which file types it needs to get rid of.
In addition, you can set it to automatically clear only the download items that have been opened or launched, and yes, it can also clear all of the items when Firefox quits.
Version reviewed: Modern Download Manager 0.2.1.1 on Firefox 43.0.4.