diff --git a/docs/operators/handbook.md b/docs/operators/handbook.md
index 211dc0e..0541441 100644
--- a/docs/operators/handbook.md
+++ b/docs/operators/handbook.md
@@ -695,3 +695,13 @@ present.
 
 However, it is otherwise **ignored** for the version candidate. The "source of
 truth" for the version candidate is the live deployment of the app.
+
+### Clean up the server
+
+When you have deployed and undeployed apps, or when you have updated apps, docker will not automatically remove the images and containers. At some point your disk will be full, and you get strange errors when trying to deploy new apps. 
+
+Log into your server with `ssh`. 
+
+You can view all information about containers and images using the command `docker system df -v`. You might see images used by 0 containers and DEAD and exited containers. 
+
+If you are *completely* SURE that you have deployed all the apps, you want to keep, you can remove all dead and unused images and containers with the command `docker system prune --all --force` (or `DOCKER_CONTEXT=foo docker system prune --all --force` if you have multiple docker contexts).