README.md

@@ -60,3 +60,8 @@ make bundle
 The output files of the final handbook can be found in the subfolder `./bundle`.
 
 All generated intermediate artifacts and the final output files can be found in the `./build` subfolder.
+
+### Clean up
+
+1. Deactivate the virtual Python environment: ```deactivate```
+2. Clean up the build sources: ```make clean``` and ```rm -r build bundle```