diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index b69134d7..513ed450 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -26,7 +26,7 @@ The development workflow is the following:
 - Run `git submodule init` and `git submodule update` to get the BATS submodules
 - Code :-)
 - Add integration tests in `test/tests.bats`
-- Use `make` to build image locally and run tests
+- Use `make clean all` to build image locally and run tests
   Note that tests work on Linux only; they hang on Mac and Windows.
 - Document your improvements in `README.md` or Wiki depending on content
 - [Commit](https://help.github.com/articles/closing-issues-via-commit-messages/), push and make a pull-request