diff --git a/tox.ini b/tox.ini
index de510c9e..73153fc8 100644
--- a/tox.ini
+++ b/tox.ini
@@ -11,6 +11,7 @@ install_command = pip install {opts} {packages}
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands =
+  /usr/bin/find . -type f -name "*.py[co]" -delete
   python setup.py testr --testr-args='{posargs}'
 
 [testenv:pep8]