diff --git a/tox.ini b/tox.ini
index aacfc76..48212b7 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,9 +7,11 @@ skipsdist = True
 usedevelop = True
 install_command = pip install -U --force-reinstall {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
+whitelist_externals = find
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands =
+    find . -type f -name "*.pyc" -delete
     ostestr {posargs}
 
 [testenv:pep8]