diff --git a/contrib/docker/Dockerfile b/contrib/docker/Dockerfile
index 17452a2d..52bdf556 100644
--- a/contrib/docker/Dockerfile
+++ b/contrib/docker/Dockerfile
@@ -21,6 +21,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     ecdsautils \
     lua-check \
     shellcheck \
+  && apt-get clean \
   && rm -rf /var/lib/apt/lists/*
 
 RUN useradd -d /gluon gluon