diff --git a/src/sat/sat_drat.cpp b/src/sat/sat_drat.cpp
index fb161a998..6d0c2979b 100644
--- a/src/sat/sat_drat.cpp
+++ b/src/sat/sat_drat.cpp
@@ -58,7 +58,6 @@ namespace sat {
     }
 
     void drat::dump(unsigned n, literal const* c, status st) {
-        if (is_cleaned(n, c)) return;
         switch (st) {
         case status::asserted: return;
         case status::external: return; // requires extension to drat format.
@@ -69,8 +68,9 @@ namespace sat {
         (*m_out) << "0\n";
     }
 
-    bool drat::is_cleaned(unsigned n, literal const* c) const {
+    bool drat::is_cleaned(clause& c) const {
         literal last = null_literal;
+        unsigned n = c.size();
         for (unsigned i = 0; i < n; ++i) {
             if (c[i] == last) return true;
             last = c[i];
@@ -133,7 +133,6 @@ namespace sat {
 
     void drat::append(clause& c, status st) {
         unsigned n = c.size();
-        if (is_cleaned(n, c.begin())) return;
         trace(std::cout, n, c.begin(), st);
 
         if (st == status::learned) {
@@ -394,10 +393,13 @@ namespace sat {
     void drat::del(literal l1, literal l2) {
         literal ls[2] = {l1, l2};
         if (m_out) dump(2, ls, status::deleted);
-        if (s.m_config.m_drat_check) append(l1, l2, status::deleted);
+        if (s.m_config.m_drat_check) 
+            append(l1, l2, status::deleted);
     }
     void drat::del(clause& c) {
         if (m_out) dump(c.size(), c.begin(), status::deleted);
-        if (s.m_config.m_drat_check) append(c, status::deleted);
+        if (s.m_config.m_drat_check) 
+            append(c, status::deleted);
+        else s.m_cls_allocator.del_clause(&c);
     }
 }
diff --git a/src/sat/sat_drat.h b/src/sat/sat_drat.h
index fd4b3f868..7236d8065 100644
--- a/src/sat/sat_drat.h
+++ b/src/sat/sat_drat.h
@@ -28,10 +28,10 @@ namespace sat {
             enum { t_clause, t_unit, t_ext } m_type;
             union {
                 clause* m_clause;
-                literal m_literal;                
+                unsigned m_literal;                
             };
-            premise(s_ext, literal l): m_type(t_ext), m_literal(l) {}
-            premise(s_unit, literal l): m_type(t_unit), m_literal(l) {}
+            premise(s_ext, literal l): m_type(t_ext), m_literal(l.index()) {}
+            premise(s_unit, literal l): m_type(t_unit), m_literal(l.index()) {}
             premise(clause* c): m_type(t_clause), m_clause(c) {}
         };
     private:
@@ -52,7 +52,6 @@ namespace sat {
         void append(clause& c, status st);
         friend std::ostream& operator<<(std::ostream & out, status st);
         status get_status(bool learned) const;
-        bool is_cleaned(unsigned n, literal const* lits) const;
 
         void declare(literal l);
         void assign(literal l);
@@ -74,7 +73,8 @@ namespace sat {
         void add(literal l1, literal l2, bool learned);
         void add(clause& c, bool learned);
         void add(literal_vector const& c, svector<premise> const& premises);
-        
+
+        bool is_cleaned(clause& c) const;        
         void del(literal l);
         void del(literal l1, literal l2);
         void del(clause& c);
diff --git a/src/sat/sat_par.cpp b/src/sat/sat_par.cpp
index ec6e39822..8d2c20d56 100644
--- a/src/sat/sat_par.cpp
+++ b/src/sat/sat_par.cpp
@@ -84,7 +84,7 @@ namespace sat {
                 break;
             }
             SASSERT(head < m_size);
-            IF_VERBOSE((iterations > m_size ? 0 : 3), verbose_stream() << owner << ": head: " << head << " tail: " << m_tail << "\n";);
+            IF_VERBOSE(static_cast<unsigned>(iterations > m_size ? 0 : 3), verbose_stream() << owner << ": head: " << head << " tail: " << m_tail << "\n";);
             bool is_self = owner == get_owner(head);
             next(m_heads[owner]);
             if (!is_self) {
diff --git a/src/sat/sat_solver.cpp b/src/sat/sat_solver.cpp
index 9b50db8e8..221140590 100644
--- a/src/sat/sat_solver.cpp
+++ b/src/sat/sat_solver.cpp
@@ -209,10 +209,10 @@ namespace sat {
         if (!c.is_learned()) {
             m_stats.m_non_learned_generation++;
         } 
-        if (m_config.m_drat) {
+        if (m_config.m_drat && !m_drat.is_cleaned(c)) {
             m_drat.del(c);
         }
-        else if (!m_config.m_drat || !m_config.m_drat_check) {
+        else if (!m_config.m_drat || !m_config.m_drat_check || m_drat.is_cleaned(c)) {
             m_cls_allocator.del_clause(&c);
         }
         m_stats.m_del_clause++;