How can I clear out my deleted files quickly?

Hello lucianolarosa !

To permanently delete files on your Dropbox Account follow the below steps:

1. Go to https://www.dropbox.com/deleted_files and sign-in
2. Then hover over the left hand side of each document/file and click on the box
3. After you have selected the files you want to permanently delete, click the button that says "Permanently Delete"
4. Done! Your files have been deleted from your Dropbox Account

I hope this helps!

This method is not quick if you have dozens, or hundreds of files to delete. How can we select all files in the "deleted files" folder?

There is no 'deleted folder' on Dropbox so there is not a quick way to do this. You can click the box at the top of the screen just above the first folders / files name at the left side. However that will also select all files and folders NOT deleted. 

They do, however, auto clear themselves (30 days if free) and do not use up quota, so, I'd not worry TOO much about deleting them. 

This doesn't help if your box is full of garbage and you can't update any files until they're removed. I only get that stupid "buy more space" notice. This is such a mafia ploy I will NEVER pay one cent to Dropbox. Using onedrive from now on.