diff --git a/tox.ini b/tox.ini
index 0271b89..0cdc37f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -12,7 +12,11 @@ setenv = VIRTUAL_ENV={envdir}
          LC_ALL=C
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
+
+whitelist_externals = find
+
 commands =
+  find . -type f -name "*.pyc" -delete
   python setup.py testr --testr-args='{posargs}'
 
 [tox:jenkins]