Another option is to map the drives that you need to access, note the drive letters assigned to each 'drive' and include them in your statement:
@echo off
del F:\sharename\*.*
del G:\sharename\*.*
del J:\sharename\*.*
exit
Write this out in notepad and save it as a .bat file on the computer where you have mapped the drives. 'del' is the command to delete, and '*.*' means all files. '@echo off' prevents each command from appearing in a DOS box. 'Exit' tells the system that the batch file has finished and the DOS session can be closed.
Next create a shortcut to the batch file. Once created, right click the file and select properties. Make sure that close on exit is selected and that it is set to run minimised.
The syntax described above is fine if you only need to delete the files from that computer. If you need to delete the files from any computer you will need to use the computername that follows the \\ symbols you see in explorer, as given in the first answer, and save the batch file to a shared folder that then be accessed from any computer on your network.
Have fun.