To find and clean-up old Git remote branches that have been merged to master

gistfile1.txt

#List all remote branches merged to master
git branch -r --merged

#For all old branches log last commit e.g.
git log --decorate -1 origin/Gauss

#To delete the branches you want
git push origin --delete Gauss

#For everyone to run locally to remove the remove references 
git remote prune origin

#To show the # of branches remaining
git branch -r | wc -l