diff --git a/Dockerfile b/Dockerfile
index 980fd35..75decec 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,7 +3,7 @@ FROM python:3-slim
 WORKDIR /
 
 # Update the image to remediate any vulnerabilities.
-RUN apt clean && apt update && apt -y dist-upgrade && apt clean
+RUN apt clean && apt update && apt -y dist-upgrade && apt clean && rm -rf /var/lib/apt/lists/*
 
 # Remove suid & sgid bits from all files.
 RUN find / -xdev -perm /6000 -exec chmod ug-s {} \; 2> /dev/null || true