How to clean project before each build?

Question

Is there a way (possibly using schemes) in Xcode to specify that a clean is automatically done before doing a new build.?

I have a project that sometimes fails to bu

Answer 1

The selected answer did not work for me, it caused my build to fail (Xcode 4.6.3) when trying to run on the simulator.
Based on Jano's answer and on this link in the Pre-action script instead of writing

rm -rf ${BUILT_PRODUCTS_DIR}  

I wrote

touch ${BUILT_PRODUCTS_DIR}

This should have the same effect and it doesn't cause my build to fail