If you have many Wi-Fi networks saved on your BlackBerry mobile device then here is a guide that let you instruct to clean up all extra Wi-Fi networks from your device, so just continue reading after the break.
Delete Wi-Fi Networks on Blackberry
Go to “Options” > “Networks and Connections” option
Select “Wi-Fi Network”
Note: If your Wi-Fi is disabled, it will ask you to enable it to proceed further.
Tap on “Saved Wi-Fi Networks”
You will find list of all Wi-Fi networks, so just select those to which you want to delete and then press menu button and select “Delete” option from list and click “OK” to confirm deletion
So, try this guide to delete extra Wi-Wi networks from your BlackBerry device.