Method 1: Folder
Delete 
The fastest way to delete files is to select the parent folder containing
all files you want to delete and click the delete button on the toolbar.
This will delete all files and folders within the selection.
Method 2: Multi-Select Search
Delete
You may also use the "Multi-Download/Search "
tab to select multiple files from different folder locations. To
do this, click on the Multi-Download/Search
tab or the Search
toolbar button to open the tab.
One by one, select the files you wish to delete and press the "Add to List >>" button to build a list of files you wish to delete. You may also use the Search feature to find files that match a file name pattern or even based on the contents of the file.
When you are done building the list of files, select all of the files you wish to delete using the mouse button and the shift key, or click the "Select All" button to highlight all files in the list. Then press the Delete button, below the list.
Method
3: Selection Basket Mass Delete
You have the option to Add any selection to the Selection Basket. This
is ultra-convenient if you are browsing through folders choosing various
files or subfolders to delete - just right-click then "Add to Selection
Basket". Your
added items will appear in the Selection Basket icon at the bottom of
the screen. You
can even add items from Search
results into the Selection Basket for later deletion, using Method 2 above
in combination with browsing folders. Click
the Selection Basket to open it up and view the items you have added.
With the
Selection Basket open, you can choose to Delete All Items in the Selection
Basket. Note:
the selection basket goes away when you log off, or if your session is
idle too long.
Method 4:
Direct WebFolder Connection to your Folders
Probably the easiest method of all for working on many files and folders
at one time is by using the WebFolder feature, available with all WebAdvanced
plans and Private Sites. With
a WebFolder connection, you can work with your files just like you do
a local drive letter. This
means you can multi-select any items you see, using just your mouse, then
right-click and choose Delete from the Windows right-click menu.
How to Map a WebFolder
WinZip is recommended to first
compress very large volumes of files before uploading. If you don't
have WinZip, you can download it from WinZip.com and try it for free.
Zip the files into a single Zip file, then upload it using the standard
Upload tab (default view). 
You can also use the Multi!Upload feature
under the Multi-Upload tab. You can upload a very large
number of files all at once by uploading the entire folder containing
these files. Click on the Multi-Upload tab, select the destination
directory, then click the "Add" button to select your local
folder. Click Multi-Upload and let