diff --git a/tools/gulp/tasks/release.ts b/tools/gulp/tasks/release.ts
index 542d4eaebac..3e089c45770 100644
--- a/tools/gulp/tasks/release.ts
+++ b/tools/gulp/tasks/release.ts
@@ -10,8 +10,9 @@ import {DIST_COMPONENTS_ROOT} from '../constants';
 
 const argv = minimist(process.argv.slice(3));
 
-
-task(':build:release:clean-spec', cleanTask('dist/**/*.spec.*'));
+/** Removes redundant spec files from the release. TypeScript creates definition files for specs. */
+// TODO(devversion): tsconfig files should share code and don't generate spec files for releases.
+task(':build:release:clean-spec', cleanTask('dist/**/*(-|.)spec.*'));
 
 
 task('build:release', function(done: () => void) {