diff --git a/nixos/machines/crash/configuration.nix b/nixos/machines/crash/configuration.nix
index 9916a6b..50138ba 100644
--- a/nixos/machines/crash/configuration.nix
+++ b/nixos/machines/crash/configuration.nix
@@ -8,11 +8,6 @@
   imports = [
   ];
 
-  nix.settings.trusted-users = [
-    "root"
-    "nathan"
-  ];
-
   programs.ssh.extraConfig = ''
     Host eu.nixbuild.net
     PubkeyAcceptedKeyTypes ssh-ed25519
@@ -29,6 +24,18 @@
   };
 
   nix = {
+    settings = {
+      auto-optimise-store = true;
+      trusted-users = [
+        "root"
+        "nathan"
+      ];
+    };
+    gc = {
+      automatic = true;
+      dates = "hourly";
+      options = "--delete-older-than 7d";
+    };
     distributedBuilds = true;
     buildMachines = [
       {