diff --git a/tools/bfdocker.sh b/tools/bfdocker.sh
index 4bb13e5..e0504c3 100755
--- a/tools/bfdocker.sh
+++ b/tools/bfdocker.sh
@@ -28,6 +28,6 @@ mkdir -p $BF_BUILD
 
 # run the command in the docker image with the same userid to avoid
 # permission problems later.
-docker run -u $(id -u) -i -t \
+docker run -u $(id -u) --rm -i -t \
     --mount type=bind,source=$BF_SOURCE,target=/source \
     $BF_DOCKER