diff --git a/bin/clean.js b/bin/clean.js
new file mode 100755
index 0000000..b75e4c0
--- /dev/null
+++ b/bin/clean.js
@@ -0,0 +1,13 @@
+#!/usr/bin/env node
+/**
+ * @file clean.js
+ * @summary prune remote and local branches, then run git garbage collection
+ */
+const { execEachRepo } = require('../lib/exec');
+
+execEachRepo([
+    'git fetch',
+    'git remote prune origin',
+    'git gc',
+]);
+
diff --git a/lib/exec.js b/lib/exec.js
new file mode 100644
index 0000000..cc3e340
--- /dev/null
+++ b/lib/exec.js
@@ -0,0 +1,39 @@
+const matrix = require("../matrix.json");
+const assert = require("assert");
+const { exec } = require("child_process");
+const fs = require("fs");
+
+const isStringArray = arr =>
+  Array.isArray(arr) && arr.every(i => typeof i === "string");
+
+/**
+ * Execute a command in each repository
+ * @param {string | string[]} command the command to run. If an array, it will be joined with `&&`.
+ */
+const execEachRepo = async command => {
+  assert(
+    typeof command === "string" || isStringArray(command),
+    "cmd must be a string or array of strings"
+  );
+  const cmd = Array.isArray(command) ? command.join(" && ") : command;
+
+  assert(
+    fs.existsSync("repos"),
+    "No repositories found, did you forget to run `pnpm clone`?"
+  );
+
+  for (const item of matrix) {
+    const command = `cd repos/${item.path} && ${cmd}`;
+    console.log(command);
+
+    exec(command, function (err) {
+      if (err) {
+        console.error(err);
+        return;
+      }
+      console.log(`Finished: ${item.repository}`);
+    });
+  }
+};
+
+module.exports = { execEachRepo };
diff --git a/package.json b/package.json
index fca7a07..22165c5 100644
--- a/package.json
+++ b/package.json
@@ -11,6 +11,7 @@
         "test:default": "RUST_BACKTRACE=1 node bin/test.js $(which oxlint)",
         "update": "node bin/update.js",
         "reset": "node bin/reset.js",
+        "clean": "node bin/clean.js",
         "lint": "npx oxlint@latest ."
     }
 }