jseed

git checkout master; git branch -D  @(git branch | select-string -NotMatch "master" | Foreach {$_.Line.Trim()})

stephenhardy

-- Remove the history from 
rm -rf .git

-- recreate the repos from the current content only
git init
git add .
git commit -m "Initial commit"

-- push to the github remote repos ensuring you overwrite history
git remote add origin git@github.com:<YOUR ACCOUNT>/<YOUR REPOS>.git