diff --git a/src/nlsat/nlsat_solver.cpp b/src/nlsat/nlsat_solver.cpp
index 882025024..6ea764a0a 100644
--- a/src/nlsat/nlsat_solver.cpp
+++ b/src/nlsat/nlsat_solver.cpp
@@ -231,6 +231,9 @@ namespace nlsat {
         }
 
         void clear() {
+            m_explain.reset();
+            m_lemma.reset();
+            m_lazy_clause.reset();
             undo_until_size(0);
             del_clauses();
             del_unref_atoms();