diff --git a/src/rapids_dependency_file_generator/cli.py b/src/rapids_dependency_file_generator/cli.py
index cf58994..450397f 100644
--- a/src/rapids_dependency_file_generator/cli.py
+++ b/src/rapids_dependency_file_generator/cli.py
@@ -1,10 +1,14 @@
 import argparse
+import os
 
 import yaml
 
 from ._version import __version__ as version
 from .constants import OutputTypes, default_dependency_file_path
-from .rapids_dependency_file_generator import make_dependency_files
+from .rapids_dependency_file_generator import (
+    delete_existing_files,
+    make_dependency_files,
+)
 from .rapids_dependency_file_validator import validate_dependencies
 
 
@@ -17,6 +21,17 @@ def validate_args(argv):
         default=default_dependency_file_path,
         help="Path to YAML config file",
     )
+    parser.add_argument(
+        "--clean",
+        nargs="?",
+        default=None,
+        const="",
+        help=(
+            "Delete any files previously created by dfg before running. An optional "
+            "path to clean may be provided, otherwise the current working directory "
+            "is used as the root from which to clean."
+        ),
+    )
 
     codependent_args = parser.add_argument_group("optional, but codependent")
     codependent_args.add_argument(
@@ -45,6 +60,11 @@ def validate_args(argv):
             + "".join([f"\n  --{x}" for x in dependent_arg_keys])
         )
 
+    # If --clean was passed without arguments, default to cleaning from the root of the
+    # tree where the config file is.
+    if args.clean == "":
+        args.clean = os.path.dirname(os.path.abspath(args.config))
+
     return args
 
 
@@ -79,4 +99,6 @@ def main(argv=None):
             }
         }
 
+    if args.clean:
+        delete_existing_files(args.clean)
     make_dependency_files(parsed_config, args.config, to_stdout)
diff --git a/src/rapids_dependency_file_generator/rapids_dependency_file_generator.py b/src/rapids_dependency_file_generator/rapids_dependency_file_generator.py
index 5d2c05b..b58ab7d 100644
--- a/src/rapids_dependency_file_generator/rapids_dependency_file_generator.py
+++ b/src/rapids_dependency_file_generator/rapids_dependency_file_generator.py
@@ -15,6 +15,27 @@
 
 OUTPUT_ENUM_VALUES = [str(x) for x in OutputTypes]
 NON_NONE_OUTPUT_ENUM_VALUES = [str(x) for x in OutputTypes if not x == OutputTypes.NONE]
+HEADER = f"# This file is generated by `{cli_name}`."
+
+
+def delete_existing_files(root="."):
+    """Delete any files generated by this generator.
+
+    This function can be used to clean up a directory tree before generating a new set
+    of files from scratch.
+
+    Parameters
+    ----------
+    root : str
+        The path to the root of the directory tree to search for files to delete.
+    """
+    for dirpath, _, filenames in os.walk(root):
+        for fn in filter(
+            lambda fn: fn.endswith(".txt") or fn.endswith(".yaml"), filenames
+        ):
+            with open(file_path := os.path.join(dirpath, fn)) as f:
+                if HEADER in f.read():
+                    os.remove(file_path)
 
 
 def dedupe(dependencies):
@@ -94,7 +115,7 @@ def make_dependency_file(
     relative_path_to_config_file = os.path.relpath(config_file, output_dir)
     file_contents = textwrap.dedent(
         f"""\
-        # This file is generated by `{cli_name}`.
+        {HEADER}
         # To make changes, edit {relative_path_to_config_file} and run `{cli_name}`.
         """
     )
diff --git a/tests/test_examples.py b/tests/test_examples.py
index 9a41b1c..fe76b90 100644
--- a/tests/test_examples.py
+++ b/tests/test_examples.py
@@ -1,7 +1,5 @@
 import glob
-import os
 import pathlib
-import shutil
 
 import jsonschema
 import pytest
@@ -20,13 +18,6 @@
 INVALID_EXAMPLE_FILES = list(CURRENT_DIR.glob("examples/invalid/*/dependencies.yaml"))
 
 
-@pytest.fixture(scope="session", autouse=True)
-def clean_actual_files():
-    for root, _, _ in os.walk("tests"):
-        if pathlib.Path(root).name == "actual":
-            shutil.rmtree(root)
-
-
 def make_file_set(file_dir):
     return {
         pathlib.Path(f).relative_to(file_dir)
@@ -56,7 +47,14 @@ def test_examples(example_dir):
     actual_dir = example_dir.joinpath("output", "actual")
     dep_file_path = example_dir.joinpath("dependencies.yaml")
 
-    main(["--config", str(dep_file_path)])
+    main(
+        [
+            "--config",
+            str(dep_file_path),
+            "--clean",
+            str(example_dir.joinpath("output", "actual")),
+        ]
+    )
 
     expected_file_set = make_file_set(expected_dir)
     actual_file_set = make_file_set(actual_dir)
@@ -75,7 +73,14 @@ def test_error_examples(test_name):
     dep_file_path = test_dir.joinpath("dependencies.yaml")
 
     with pytest.raises(ValueError):
-        main(["--config", str(dep_file_path)])
+        main(
+            [
+                "--config",
+                str(dep_file_path),
+                "--clean",
+                str(test_dir.joinpath("output", "actual")),
+            ]
+        )
 
 
 def test_examples_are_valid(schema, example_dir):