diff --git a/README.md b/README.md
index f38e845..ddd6844 100644
--- a/README.md
+++ b/README.md
@@ -41,6 +41,14 @@ To rollback to the previous generation:
 just rollback
 ```
 
+## Garbage collection
+
+To cleanup previous files, run nix garbage collection:
+
+```sh
+just clean
+```
+
 ## Pre-commit hooks
 
 Pre-commit hooks are automatically activated when [direnv](https://github.com/direnv/direnv) is installed.
diff --git a/justfile b/justfile
index 6965e72..fbd5e12 100644
--- a/justfile
+++ b/justfile
@@ -16,3 +16,9 @@ update:
 
 fmt:
 	nixpkgs-fmt .
+
+clean:
+  echo 'Cleaning user...'
+  nix-collect-garbage -d
+  echo 'Cleaning root...'
+  sudo nix-collect-garbage -d