$ git gc --prune=now
git-gc - Cleanup unnecessary files and optimize the local repository
git gc [–aggressive] [–auto] [–quiet] [–prune=
Runs a number of housekeeping tasks within the current >repository, such as compressing file revisions (to reduce disk space and increase performance) and removing unreachable objects which may have been created from prior invocations of git add. Users are encouraged to run this task on a regular basis within each repository to maintain good disk space utilization and good operating performance.
git-remote - manage set of tracked repositories
git remote prune [-n | –dry-run]
Deletes all stale remote-tracking branches under <name>. These stale branches have already been removed from the remote repository referenced by <name>, but are still locally available in "remotes/<name>".