diff --git a/Makefile b/Makefile
index cdfe40d..d97d890 100644
--- a/Makefile
+++ b/Makefile
@@ -60,6 +60,9 @@ prepare: clean
 $(CDX):
 #	dependencies is here to not re-build on every make
 	@make -C $(PWD) prepare $(CLSS)
+	@echo Removing R classes
+	@find $(GEN) -name 'R.class' -exec rm {} \;
+	@find $(GEN) -name 'R$$*.class' -exec rm {} \;
 	@$(DX) --dex --output=$@ $(GEN)
 
 $(GEN)/%.class: $(SRC)/%.java