diff --git a/src/query.c b/src/query.c
index 9066a7d9..2a008fc8 100644
--- a/src/query.c
+++ b/src/query.c
@@ -909,13 +909,13 @@ static bool resume_any_choices(const query *q, const frame *f)
 
 static void trim_frame(query *q, const frame *f)
 {
-#if 0
 	for (unsigned i = 0; i < f->actual_slots; i++) {
 		slot *e = GET_SLOT(f, i);
 		cell *c = &e->c;
 		unshare_cell(c);
+		c->tag = TAG_EMPTY;
+		c->flags = 0;
 	}
-#endif
 
 	q->st.sp -= f->actual_slots;
 	q->st.fp--;