diff --git a/src/index.js b/src/index.js
index 47f6019..dd5a9bf 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,5 +1,6 @@
 import gulp from 'gulp';
 import gulpZip from 'gulp-zip';
+import del from 'del';
 import { join } from 'path';
 import { promiseFromObjectStream } from './p-stream.js';
 import fs from 'fs-extra';
@@ -38,4 +39,11 @@ export async function build ({ cwd, out, manifest, reporter, options }) {
   );
 
   reporter.created(join(out, ZIP_FILENAME), `zip:dependencies`);
+
+  try {
+    await del([join(tempWorkingDir, '*')]);
+  } catch (er) {
+    // If this fails, it's not a big deal. We'll likely get a non-zero
+    // exit code though
+  }
 }