diff --git a/src/pebblisp.c b/src/pebblisp.c
index 498069b..bd25c56 100644
--- a/src/pebblisp.c
+++ b/src/pebblisp.c
@@ -340,14 +340,14 @@ Object filter(Object obj1, Object obj2, struct Environment *env)
 Object append(Object list, Object newElement, struct Environment *env)
 {
     Object newList = cloneObject(list);
-    nf_addToList(&newList, newElement);
+    nf_addToList(&newList, cloneObject(newElement));
     return newList;
 }
 
 Object prepend(Object list, Object newElement, struct Environment *env)
 {
     Object newList = listObject();
-    nf_addToList(&newList, newElement);
+    nf_addToList(&newList, cloneObject(newElement));
     appendList(&newList, &list);
     return newList;
 }
@@ -364,7 +364,7 @@ Object rest(Object list, Object ignore, struct Environment *env)
     FOR_POINTER_IN_LIST(l) {
         if(POINTER == l->list)
             continue;
-        nf_addToList(&ret, *POINTER);
+        nf_addToList(&ret, cloneObject(*POINTER));
     }
     return ret;
 }