diff --git a/openjdk-7-jre/Dockerfile b/openjdk-7-jre/Dockerfile
index 10be788..166fa7d 100644
--- a/openjdk-7-jre/Dockerfile
+++ b/openjdk-7-jre/Dockerfile
@@ -12,6 +12,7 @@ FROM dockerfile/ubuntu
 RUN \
   apt-get update && \
   apt-get install -y openjdk-7-jre && \
+  apt-get clean && \
   rm -rf /var/lib/apt/lists/*
 
 # Define working directory.