diff --git a/docker/MON/Dockerfile b/docker/MON/Dockerfile
index 7daa774..719d633 100644
--- a/docker/MON/Dockerfile
+++ b/docker/MON/Dockerfile
@@ -55,7 +55,8 @@
 RUN DEBIAN_FRONTEND=noninteractive apt-get --yes update && \
     DEBIAN_FRONTEND=noninteractive apt-get --yes install \
     python3-minimal=3.8.* \
-    ca-certificates
+    ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
 
 COPY --from=INSTALL /usr/lib/python3/dist-packages /usr/lib/python3/dist-packages
 COPY --from=INSTALL /usr/local/lib/python3.8/dist-packages  /usr/local/lib/python3.8/dist-packages