diff --git a/README.md b/README.md
index 3a1f0b2..5be6ac5 100644
--- a/README.md
+++ b/README.md
@@ -57,6 +57,9 @@ script from the project's base directory.
 
 `build` and `build.sh` accept the environment variables `CXX` and `CXXFLAGS`. `CXXFLAGS` must at least specify the C++ version.
 
+To clean out the build or dependency directories, use `clean` and `clean_dependencies` or their corresponding scripts respectively. `setup_project` will clean out both before doing its thing.
+
+
 ## Copyright / License
 
 See the file [`COPYING`](./COPYING) for copyright information.