diff --git a/checker/bin-devel/test-cftests-junit.sh b/checker/bin-devel/test-cftests-junit.sh
index eaf78761af0..bd4d3884ec5 100755
--- a/checker/bin-devel/test-cftests-junit.sh
+++ b/checker/bin-devel/test-cftests-junit.sh
@@ -13,3 +13,7 @@ source "$SCRIPTDIR"/clone-related.sh
 # Adding --max-workers=1 to avoid random failures in Github Actions. An alternative solution is to use --no-build-cache.
 # https://github.com/eisop/checker-framework/issues/849
 ./gradlew test -x javadoc -x allJavadoc --console=plain --warning-mode=all --max-workers=1
+
+# Test clean task
+./gradlew clean
+./gradlew clean
diff --git a/checker/tests/nullness-extra/issue265/Makefile b/checker/tests/nullness-extra/issue265/Makefile
index 117806bff93..aafacf9ecd2 100644
--- a/checker/tests/nullness-extra/issue265/Makefile
+++ b/checker/tests/nullness-extra/issue265/Makefile
@@ -6,5 +6,4 @@ all:
 	$(JAVAC) -processor org.checkerframework.checker.nullness.NullnessChecker Delta.java -cp bin/ -d bin/
 
 clean:
-	rm bin/*.class
-	rmdir bin
+	rm -rf bin
diff --git a/docs/examples/BazelExample/Makefile b/docs/examples/BazelExample/Makefile
index 8e124e1aba3..ede061d1c46 100644
--- a/docs/examples/BazelExample/Makefile
+++ b/docs/examples/BazelExample/Makefile
@@ -5,5 +5,5 @@ all:
 	grep -qF "BazelExample.java:25: error: [assignment.type.incompatible] incompatible types in assignment." Out.txt || (echo "FAILURE.  Here is file Out.txt:" && cat Out.txt && echo "End of file Out.txt." && false)
 
 clean:
-	bazelisk clean
+	-bazelisk clean
 	rm -f Out.txt
diff --git a/docs/examples/errorprone/Makefile b/docs/examples/errorprone/Makefile
index 392ab070cb1..c82ed0cd3d5 100644
--- a/docs/examples/errorprone/Makefile
+++ b/docs/examples/errorprone/Makefile
@@ -8,5 +8,5 @@ all:
 	grep -qF "Demo.java:8: error: [argument.type.incompatible] incompatible argument for parameter arg0 of Set.add." Out.txt
 
 clean:
-	../../../gradlew clean
+	- ../../../gradlew clean
 	rm -f Out.txt
diff --git a/docs/examples/lombok/Makefile b/docs/examples/lombok/Makefile
index fad2c712390..3cd6a335b59 100644
--- a/docs/examples/lombok/Makefile
+++ b/docs/examples/lombok/Makefile
@@ -18,5 +18,5 @@ all:
 endif
 
 clean:
-	../../../gradlew clean
+	- ../../../gradlew clean
 	rm -f Out.txt