From Juneday education
Remove untracked files
git clean -fx
-x Don’t use the standard ignore rules read from .gitignore (per directory) and $GIT_DIR/info/exclude, but do still use the ignore rules given with -e options. This allows removing all untracked files, including build products. This can be used (possibly in conjunction with git reset) to create a pristine working directory to test a clean build.
git clean -fX
-X Remove only files ignored by Git. This may be useful to rebuild everything from scratch, but keep manually created files.
git status --ignored - list untracked files