SOLVED: Juniper Error J-Web is unable to access user information as the device file system is full. Please clear the storage from CLI using (request system storage cleanup) to continue with J-web access

If you have were trying to upgrade your Juniper device (like a Juniper SRX product) and were prompted with a error message telling you that your Juniper device was out of space like:

J-Web is unable to access user information as the device file system is full. Please clear the storage from CLI using (request system storage cleanup) to continue with J-web access.

then you need to clear out some dead files and logs from that Juniper firewall or switch.  They question is how can I easily make space on my Juniper hardware and the answer is to:

1. Use a terminal (like Putty) to SSH to your Juniper switch or firewall
2. Enter the ROOT username and password when prompted
3. Type CLI and then press the enter key to bring up the Command Line Interface
4. Type request system storage cleanup and press the enter key
5. Wait about a minute as Junos scans the device for unnecessary files
6. Type Y and press the enter key to delete the surplus files
7. Try your upgrade again.

I put together a brief video for you to see these instructions executed in Juniper CLI in case the above is not clear.