diff --git a/CHANGES.txt b/CHANGES.txt
index 7126f53e72..1777b8dd99 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -8,6 +8,7 @@
  * Make sure sstables with moved starts are removed correctly in LeveledGenerations (CASSANDRA-16552)
  * Upgrade jackson-databind to 2.9.10.8 (CASSANDRA-16462)
 Merged from 3.0:
+ * Clean transaction log leftovers at the beginning of sstablelevelreset and sstableofflinerelevel (CASSANDRA-12519)
  * CQL shell should prefer newer TLS version by default (CASSANDRA-16695)
  * Ensure that existing empty rows are properly returned (CASSANDRA-16671)
  * Invalidate prepared statements on DROP COMPACT (CASSANDRA-16712)
diff --git a/src/java/org/apache/cassandra/tools/SSTableLevelResetter.java b/src/java/org/apache/cassandra/tools/SSTableLevelResetter.java
index 915edf12b7..40cdd7b2e8 100644
--- a/src/java/org/apache/cassandra/tools/SSTableLevelResetter.java
+++ b/src/java/org/apache/cassandra/tools/SSTableLevelResetter.java
@@ -22,6 +22,7 @@ import java.util.Map;
 import java.util.Set;
 
 import org.apache.cassandra.config.Schema;
+import org.apache.cassandra.db.lifecycle.LifecycleTransaction;
 import org.apache.cassandra.db.ColumnFamilyStore;
 import org.apache.cassandra.db.Directories;
 import org.apache.cassandra.db.Keyspace;
@@ -75,10 +76,19 @@ public class SSTableLevelResetter
                 System.exit(1);
             }
 
+            // remove any leftovers in the transaction log
             Keyspace keyspace = Keyspace.openWithoutSSTables(keyspaceName);
             ColumnFamilyStore cfs = keyspace.getColumnFamilyStore(columnfamily);
+            if (!LifecycleTransaction.removeUnfinishedLeftovers(cfs))
+            {
+                throw new RuntimeException(String.format("Cannot remove temporary or obsoleted files for %s.%s " +
+                                                         "due to a problem with transaction log files.",
+                                                         keyspace, columnfamily));
+            }
+
+            Directories.SSTableLister lister = cfs.getDirectories().sstableLister(Directories.OnTxnErr.THROW).skipTemporary(true);
             boolean foundSSTable = false;
-            for (Map.Entry<Descriptor, Set<Component>> sstable : cfs.getDirectories().sstableLister(Directories.OnTxnErr.THROW).list().entrySet())
+            for (Map.Entry<Descriptor, Set<Component>> sstable : lister.list().entrySet())
             {
                 if (sstable.getValue().contains(Component.STATS))
                 {
diff --git a/src/java/org/apache/cassandra/tools/SSTableOfflineRelevel.java b/src/java/org/apache/cassandra/tools/SSTableOfflineRelevel.java
index 9f0395b0fc..ae0242cfd6 100644
--- a/src/java/org/apache/cassandra/tools/SSTableOfflineRelevel.java
+++ b/src/java/org/apache/cassandra/tools/SSTableOfflineRelevel.java
@@ -35,6 +35,7 @@ import com.google.common.collect.Multimap;
 import com.google.common.collect.SetMultimap;
 
 import org.apache.cassandra.config.Schema;
+import org.apache.cassandra.db.lifecycle.LifecycleTransaction;
 import org.apache.cassandra.db.ColumnFamilyStore;
 import org.apache.cassandra.db.DecoratedKey;
 import org.apache.cassandra.db.Directories;
@@ -97,8 +98,16 @@ public class SSTableOfflineRelevel
                     keyspace,
                     columnfamily));
 
+        // remove any leftovers in the transaction log
         Keyspace ks = Keyspace.openWithoutSSTables(keyspace);
         ColumnFamilyStore cfs = ks.getColumnFamilyStore(columnfamily);
+        if (!LifecycleTransaction.removeUnfinishedLeftovers(cfs))
+        {
+            throw new RuntimeException(String.format("Cannot remove temporary or obsoleted files for %s.%s " +
+                                                     "due to a problem with transaction log files.",
+                                                     keyspace, columnfamily));
+        }
+
         Directories.SSTableLister lister = cfs.getDirectories().sstableLister(Directories.OnTxnErr.THROW).skipTemporary(true);
         SetMultimap<File, SSTableReader> sstableMultimap = HashMultimap.create();
         for (Map.Entry<Descriptor, Set<Component>> sstable : lister.list().entrySet())