diff --git a/recipe_modules/repo_util/api.py b/recipe_modules/repo_util/api.py
index 4cfac43..5db0549 100644
--- a/recipe_modules/repo_util/api.py
+++ b/recipe_modules/repo_util/api.py
@@ -127,6 +127,12 @@
       # automatically deleted for example when try bots checkout an old hash.
       clobber = True
 
+      # Try doing a git clean of every repository.
+      # This is an experiment that may serve as a faster alternative to
+      # clobbering the entire cache for release branch builds.
+      with self.m.context(cwd=checkout_path):
+        self.m.gclient('git clean all repos', ['recurse', 'git', 'clean', '-fdx'])
+
     engine_repo = 'flutter' if self.is_fusion() else 'engine'
     git_url = REPOS[engine_repo]
     git_id = self.m.buildbucket.gitiles_commit.id
diff --git a/recipe_modules/repo_util/examples/full.expected/force_get_candidate_branch.json b/recipe_modules/repo_util/examples/full.expected/force_get_candidate_branch.json
index 13b8b25..0ebbdbe 100644
--- a/recipe_modules/repo_util/examples/full.expected/force_get_candidate_branch.json
+++ b/recipe_modules/repo_util/examples/full.expected/force_get_candidate_branch.json
@@ -53,7 +53,7 @@
       "           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^",
       "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/examples/full.py\", line 28, in RunSteps",
       "    api.repo_util.release_candidate_branch(flutter_checkout_path)",
-      "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/api.py\", line 618, in release_candidate_branch",
+      "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/api.py\", line 624, in release_candidate_branch",
       "    raise ValueError('Not a release candidate branch: %s' % candidate_branch)",
       "ValueError: Not a release candidate branch: refs/pull/1/head"
     ]
diff --git a/recipe_modules/repo_util/examples/full.expected/mac.json b/recipe_modules/repo_util/examples/full.expected/mac.json
index c298036..6994b5e 100644
--- a/recipe_modules/repo_util/examples/full.expected/mac.json
+++ b/recipe_modules/repo_util/examples/full.expected/mac.json
@@ -768,6 +768,25 @@
     "name": "ensure directory"
   },
   {
+    "cmd": [
+      "vpython3",
+      "-u",
+      "RECIPE_REPO[depot_tools]/gclient.py",
+      "recurse",
+      "git",
+      "clean",
+      "-fdx"
+    ],
+    "cwd": "[START_DIR]/engine",
+    "env_suffixes": {
+      "PATH": [
+        "RECIPE_REPO[depot_tools]"
+      ]
+    },
+    "infra_step": true,
+    "name": "gclient git clean all repos"
+  },
+  {
     "cmd": [],
     "name": "Checkout source code"
   },
diff --git a/recipe_modules/repo_util/examples/full.expected/mac_release_candidate.json b/recipe_modules/repo_util/examples/full.expected/mac_release_candidate.json
index fe01cc0..1dd83ca 100644
--- a/recipe_modules/repo_util/examples/full.expected/mac_release_candidate.json
+++ b/recipe_modules/repo_util/examples/full.expected/mac_release_candidate.json
@@ -808,6 +808,25 @@
     "name": "ensure directory"
   },
   {
+    "cmd": [
+      "vpython3",
+      "-u",
+      "RECIPE_REPO[depot_tools]/gclient.py",
+      "recurse",
+      "git",
+      "clean",
+      "-fdx"
+    ],
+    "cwd": "[START_DIR]/engine",
+    "env_suffixes": {
+      "PATH": [
+        "RECIPE_REPO[depot_tools]"
+      ]
+    },
+    "infra_step": true,
+    "name": "gclient git clean all repos"
+  },
+  {
     "cmd": [],
     "name": "Checkout source code"
   },
diff --git a/recipe_modules/repo_util/examples/full.expected/mac_release_candidate_sha_mismatch.json b/recipe_modules/repo_util/examples/full.expected/mac_release_candidate_sha_mismatch.json
index d6fc49e..985aebf 100644
--- a/recipe_modules/repo_util/examples/full.expected/mac_release_candidate_sha_mismatch.json
+++ b/recipe_modules/repo_util/examples/full.expected/mac_release_candidate_sha_mismatch.json
@@ -788,6 +788,25 @@
     "name": "ensure directory"
   },
   {
+    "cmd": [
+      "vpython3",
+      "-u",
+      "RECIPE_REPO[depot_tools]/gclient.py",
+      "recurse",
+      "git",
+      "clean",
+      "-fdx"
+    ],
+    "cwd": "[START_DIR]/engine",
+    "env_suffixes": {
+      "PATH": [
+        "RECIPE_REPO[depot_tools]"
+      ]
+    },
+    "infra_step": true,
+    "name": "gclient git clean all repos"
+  },
+  {
     "cmd": [],
     "name": "Checkout source code"
   },
diff --git a/recipe_modules/repo_util/examples/full.expected/monorepo_wrong_host.json b/recipe_modules/repo_util/examples/full.expected/monorepo_wrong_host.json
index 72b9db1..fd9532e 100644
--- a/recipe_modules/repo_util/examples/full.expected/monorepo_wrong_host.json
+++ b/recipe_modules/repo_util/examples/full.expected/monorepo_wrong_host.json
@@ -1044,7 +1044,7 @@
       "           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^",
       "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/examples/full.py\", line 54, in RunSteps",
       "    api.repo_util.monorepo_checkout(checkout_path, {}, {})",
-      "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/api.py\", line 221, in monorepo_checkout",
+      "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/api.py\", line 227, in monorepo_checkout",
       "    raise ValueError(",
       "ValueError: Input reference is not on dart.googlesource.com/monorepo"
     ]
diff --git a/recipe_modules/repo_util/examples/full.expected/win.json b/recipe_modules/repo_util/examples/full.expected/win.json
index 24418a1..f985baa 100644
--- a/recipe_modules/repo_util/examples/full.expected/win.json
+++ b/recipe_modules/repo_util/examples/full.expected/win.json
@@ -767,6 +767,25 @@
     "name": "ensure directory"
   },
   {
+    "cmd": [
+      "vpython3",
+      "-u",
+      "RECIPE_REPO[depot_tools]\\gclient.py",
+      "recurse",
+      "git",
+      "clean",
+      "-fdx"
+    ],
+    "cwd": "[START_DIR]\\engine",
+    "env_suffixes": {
+      "PATH": [
+        "RECIPE_REPO[depot_tools]"
+      ]
+    },
+    "infra_step": true,
+    "name": "gclient git clean all repos"
+  },
+  {
     "cmd": [],
     "name": "Checkout source code"
   },
diff --git a/recipe_modules/repo_util/examples/unsupported.expected/unsupported.json b/recipe_modules/repo_util/examples/unsupported.expected/unsupported.json
index 3fb0f42..17bdd01 100644
--- a/recipe_modules/repo_util/examples/unsupported.expected/unsupported.json
+++ b/recipe_modules/repo_util/examples/unsupported.expected/unsupported.json
@@ -21,7 +21,7 @@
       "           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^",
       "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/examples/unsupported.py\", line 13, in RunSteps",
       "    api.repo_util.checkout('unsupported_repo', repo_dir)",
-      "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/api.py\", line 287, in checkout",
+      "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/api.py\", line 293, in checkout",
       "    raise ValueError('Unsupported repo: %s' % name)",
       "ValueError: Unsupported repo: unsupported_repo"
     ]
diff --git a/recipes/engine_v2/builder.expected/dart-internal-flutter-success.json b/recipes/engine_v2/builder.expected/dart-internal-flutter-success.json
index 3474bae..6440ce4 100644
--- a/recipes/engine_v2/builder.expected/dart-internal-flutter-success.json
+++ b/recipes/engine_v2/builder.expected/dart-internal-flutter-success.json
@@ -216,6 +216,40 @@
     ]
   },
   {
+    "cmd": [
+      "vpython3",
+      "-u",
+      "RECIPE_REPO[depot_tools]/gclient.py",
+      "recurse",
+      "git",
+      "clean",
+      "-fdx"
+    ],
+    "cwd": "[CACHE]/builder",
+    "env": {
+      "DEPOT_TOOLS_REPORT_BUILD": "dart-internal/flutter/builder/8945511751514863184"
+    },
+    "env_suffixes": {
+      "PATH": [
+        "RECIPE_REPO[depot_tools]"
+      ]
+    },
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "dart-internal:flutter"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "gclient git clean all repos"
+  },
+  {
     "cmd": [],
     "name": "Checkout source code"
   },
diff --git a/recipes/engine_v2/builder.expected/test_if_skip_presubmit.json b/recipes/engine_v2/builder.expected/test_if_skip_presubmit.json
index 320db0b..8cc0c2d 100644
--- a/recipes/engine_v2/builder.expected/test_if_skip_presubmit.json
+++ b/recipes/engine_v2/builder.expected/test_if_skip_presubmit.json
@@ -165,6 +165,40 @@
     ]
   },
   {
+    "cmd": [
+      "vpython3",
+      "-u",
+      "RECIPE_REPO[depot_tools]/gclient.py",
+      "recurse",
+      "git",
+      "clean",
+      "-fdx"
+    ],
+    "cwd": "[CACHE]/builder",
+    "env": {
+      "DEPOT_TOOLS_REPORT_BUILD": "flutter/prod/linux-host/8945511751514863184"
+    },
+    "env_suffixes": {
+      "PATH": [
+        "RECIPE_REPO[depot_tools]"
+      ]
+    },
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "flutter:prod"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "gclient git clean all repos"
+  },
+  {
     "cmd": [],
     "name": "Checkout source code"
   },
diff --git a/recipes/engine_v2/engine_v2.expected/basic_mac_dart_internal.json b/recipes/engine_v2/engine_v2.expected/basic_mac_dart_internal.json
index 814763b..e4ba60c 100644
--- a/recipes/engine_v2/engine_v2.expected/basic_mac_dart_internal.json
+++ b/recipes/engine_v2/engine_v2.expected/basic_mac_dart_internal.json
@@ -451,6 +451,40 @@
     ]
   },
   {
+    "cmd": [
+      "vpython3",
+      "-u",
+      "RECIPE_REPO[depot_tools]/gclient.py",
+      "recurse",
+      "git",
+      "clean",
+      "-fdx"
+    ],
+    "cwd": "[CACHE]/builder",
+    "env": {
+      "DEPOT_TOOLS_REPORT_BUILD": "dart-internal/flutter/prod-builder/8945511751514863184"
+    },
+    "env_suffixes": {
+      "PATH": [
+        "RECIPE_REPO[depot_tools]"
+      ]
+    },
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "dart-internal:flutter"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "gclient git clean all repos"
+  },
+  {
     "cmd": [],
     "name": "Checkout source code"
   },