diff --git a/build-book-converter.jenkins b/build-book-converter.jenkins
index 8f2a74c..da9fc6a 100644
--- a/build-book-converter.jenkins
+++ b/build-book-converter.jenkins
@@ -38,6 +38,7 @@ COPY entrypoint.sh /calibre/entrypoint.sh
 RUN apt-get update && \\
     apt-get upgrade -y && \\
     apt-get install -y --no-install-recommends curl xz-utils libgl1 libxcb1 && \\
+    apt-get clean && \\
     chmod +x /calibre/entrypoint.sh && \\
     mkdir -p /opt/calibre && \\
     curl -Lks "https://nexus.c.test-chamber-13.lan/repository/calibre/${calibreVer}/calibre-${calibreVer}-x86_64.txz" -o /tmp/calibre.tar.xz && \\