diff --git a/build/bin/Dockerfile b/build/bin/Dockerfile
index d3429cad..0317e72f 100644
--- a/build/bin/Dockerfile
+++ b/build/bin/Dockerfile
@@ -2,9 +2,11 @@
 
 FROM debian:9
 
-RUN apt-get update && apt-get install -y \
-    build-essential git wget pkg-config lxc-dev libzmq3-dev libgflags-dev \
-    libsnappy-dev zlib1g-dev libbz2-dev liblz4-dev graphviz upx-ucl
+RUN apt-get update && \
+    apt-get install -y build-essential git wget pkg-config lxc-dev libzmq3-dev \
+                       libgflags-dev libsnappy-dev zlib1g-dev libbz2-dev \
+                       liblz4-dev graphviz upx-ucl && \
+    apt-get clean
 
 ENV GOLANG_VERSION=go1.10.linux-amd64
 ENV GOPATH=/go
diff --git a/build/deb/Dockerfile b/build/deb/Dockerfile
index 5782d98b..bb0f3d56 100644
--- a/build/deb/Dockerfile
+++ b/build/deb/Dockerfile
@@ -2,8 +2,9 @@
 
 FROM blockbook-build:latest
 
-RUN apt-get update && apt-get install -y \
-    devscripts debhelper make dh-systemd dh-exec
+RUN apt-get update && \
+    apt-get install -y devscripts debhelper make dh-systemd dh-exec && \
+    apt-get clean
 
 ADD build-deb.sh /build/build-deb.sh