(Inspired by https://medium.com/@icanhazedit/clean-up-unused-github-rpositories-c2549294ee45#.3hwv4nxv5)
- 
Open in a new tab all to-be-deleted github repositores (Use the mouse’s middle click or Ctrl + Click) https://github.com/username?tab=repositories
 - 
Use one tab https://chrome.google.com/webstore/detail/onetab/chphlpgkkbolifaimnlloiipkdnihall to shorten them to a list.
 - 
Save that list to some path
 - 
The list should be in the form of “ur_username\repo_name” per line. Use regex search (Sublime text could help). Search for ' |.*' and replace by empty.