# nix-collect-garbage > Delete unused and unreachable nix store paths. > Generations can be listed using `nix-env --list-generations`. > More information: . - Delete all store paths unused by current generations of each profile: `sudo nix-collect-garbage --delete-old` - Simulate the deletion of old store paths: `sudo nix-collect-garbage --delete-old --dry-run` - Delete all store paths older than 30 days: `sudo nix-collect-garbage --delete-older-than 30d`