For some projects, the workflow I use in Git is to create a new branch for every new feature or bug fix. This works well for keeping things separate, but it does result in a lot of branches lying around which are no longer needed after they’ve been merged into master. There are a few steps which will clean up old branches one at a time.
First of all, to remove the branch from the remote, push as you normally would but place a colon in front of the branch name:
git push origin :mybranch
Then delete your local copy of the branch:
git branch --delete mybranch
Anyone else with a copy of the repository can then run the following command to prune their list of remote branches:
git fetch origin --prune
You can use -d instead of --delete and -p in place of --prune.