Make sure that latest Nokia Suite is installed on your phone, but it is not running in the background. We only need the connectivity drivers from Nokia Suite.

Connect to your Mobile file system

Download MobiMB software. Link Here
Double Click to open the downloaded file (MobiMB.exe) and choose the location where you wanna extract the setup files to.
Browse to the folder where you extracted files in the previous step and run setup.exe
Continue with the setup by accepting license agreement.
Keep the shortcut at the desktop and finish the setup.
Now connect your phone to your PC and run the MobiMB Mobile Media Browser shortcut from the desktop.
Click on Start MobiMB.

Now click on

File> Settings.
choose Add a new Connection>

Cable Connection>

Nokia native USB phones>

CA-101 cable (Micro-USB). Press OK

Wooh!! You’ll be presented with your phone’s file-system. Access and add/remove the files you want. Read below if you don’t know what to delete.

Which files can I delete without the risk

MobiMB> Games and Apps: (Includes /collections and /games) You can delete all the pre-installed games and apps that you don’t need in your phone. For games and apps, you can delete the jar and jad files, but you might be unable to delete the folder for private files of such apps. Just ignore it as it does not contain any data larger than a few KBs.