diff --git a/src/python/cram/__main__.py b/src/python/cram/__main__.py
index 699f92b..eba6548 100644
--- a/src/python/cram/__main__.py
+++ b/src/python/cram/__main__.py
@@ -124,8 +124,8 @@ def load_state(statefile: Path) -> Vfs:
 def simplify(old_fs: Vfs, new_fs: Vfs, /, exec_idempotent=True) -> Vfs:
     """Try to reduce a new VFS using diff from the original VFS."""
 
-    old_fs = old_fs.copy()
-    new_fs = new_fs.copy()
+    old_fs = old_fs.clone()
+    new_fs = new_fs.clone()
 
     # Scrub anything in the new log that's in the old log
     for txn in list(old_fs._log):
@@ -154,8 +154,8 @@ def simplify(old_fs: Vfs, new_fs: Vfs, /, exec_idempotent=True) -> Vfs:
 def scrub(old_fs: Vfs, new_fs: Vfs) -> Vfs:
     """Try to eliminate files which were previously installed but are no longer used."""
 
-    old_fs = old_fs.copy()
-    new_fs = new_fs.copy()
+    old_fs = old_fs.clone()
+    new_fs = new_fs.clone()
     cleanup_fs = Vfs([])
 
     # Look for files in the old log which are no longer present in the new log