diff --git a/swh/storage/buffer.py b/swh/storage/buffer.py
--- a/swh/storage/buffer.py
+++ b/swh/storage/buffer.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2019 The Software Heritage developers
+# Copyright (C) 2019-2020 The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
@@ -115,3 +115,21 @@
             return self.flush()
 
         return {}
+
+    def clear_buffers(
+            self, object_types: Optional[Iterable[str]] = None) -> None:
+        """Clear objects from current buffer.
+
+        WARNING:
+
+            data that has not been flushed to storage will be lost when this
+            method is called. This should only be called when `flush` fails and
+            you want to continue your processing.
+
+        """
+        if object_types is None:
+            object_types = self.object_types
+
+        for object_type in object_types:
+            q = self._objects[object_type]
+            q.clear()
diff --git a/swh/storage/cassandra/storage.py b/swh/storage/cassandra/storage.py
--- a/swh/storage/cassandra/storage.py
+++ b/swh/storage/cassandra/storage.py
@@ -979,3 +979,10 @@
     def metadata_provider_get_by(self, provider):
         # TODO
         raise NotImplementedError('not yet supported for Cassandra')
+
+    def clear_buffers(
+            self, object_types: Optional[Iterable[str]] = None) -> None:
+        """Do nothing
+
+        """
+        return None
diff --git a/swh/storage/filter.py b/swh/storage/filter.py
--- a/swh/storage/filter.py
+++ b/swh/storage/filter.py
@@ -1,10 +1,10 @@
-# Copyright (C) 2019 The Software Heritage developers
+# Copyright (C) 2019-2020 The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 
-from typing import Dict, Iterable, Set
+from typing import Dict, Iterable, Optional, Set
 
 from swh.model.model import (
     Content, SkippedContent, Directory, Revision,
@@ -149,3 +149,9 @@
 
         fn = fn_by_object_type[object_type]
         return set(fn(missing_ids))
+
+    def clear_buffers(
+            self, object_types: Optional[Iterable[str]] = None) -> None:
+        if hasattr(self.storage, 'clear_buffers'):
+            return self.storage.clear_buffers(object_types)
+        return None
diff --git a/swh/storage/in_memory.py b/swh/storage/in_memory.py
--- a/swh/storage/in_memory.py
+++ b/swh/storage/in_memory.py
@@ -1005,3 +1005,10 @@
 
     def diff_revision(self, revision, track_renaming=False):
         raise NotImplementedError('InMemoryStorage.diff_revision')
+
+    def clear_buffers(
+            self, object_types: Optional[Iterable[str]] = None) -> None:
+        """Do nothing
+
+        """
+        return None
diff --git a/swh/storage/retry.py b/swh/storage/retry.py
--- a/swh/storage/retry.py
+++ b/swh/storage/retry.py
@@ -149,3 +149,9 @@
         if hasattr(self.storage, 'flush'):
             return self.storage.flush(object_types)
         return {}
+
+    def clear_buffers(
+            self, object_types: Optional[Iterable[str]] = None) -> None:
+        if hasattr(self.storage, 'clear_buffers'):
+            return self.storage.clear_buffers(object_types)
+        return None
diff --git a/swh/storage/storage.py b/swh/storage/storage.py
--- a/swh/storage/storage.py
+++ b/swh/storage/storage.py
@@ -1152,3 +1152,10 @@
     @timed
     def diff_revision(self, revision, track_renaming=False):
         return diff.diff_revision(self, revision, track_renaming)
+
+    def clear_buffers(
+            self, object_types: Optional[Iterable[str]] = None) -> None:
+        """Do nothing
+
+        """
+        return None
diff --git a/swh/storage/tests/test_buffer.py b/swh/storage/tests/test_buffer.py
--- a/swh/storage/tests/test_buffer.py
+++ b/swh/storage/tests/test_buffer.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2019 The Software Heritage developers
+# Copyright (C) 2019-2020 The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
@@ -277,3 +277,69 @@
 
     s = storage.flush()
     assert s == {}
+
+
+def test_buffering_proxy_storage_clear(sample_data):
+    """Clear operation on buffer
+
+    """
+    threshold = 10
+    contents = sample_data['content']
+    assert 0 < len(contents) < threshold
+    skipped_contents = sample_data['skipped_content']
+    assert 0 < len(skipped_contents) < threshold
+    directories = sample_data['directory']
+    assert 0 < len(directories) < threshold
+    revisions = sample_data['revision']
+    assert 0 < len(revisions) < threshold
+    releases = sample_data['release']
+    assert 0 < len(releases) < threshold
+
+    storage = get_storage_with_buffer_config(
+        min_batch_size={
+            'content': threshold,
+            'skipped_content': threshold,
+            'directory': threshold,
+            'revision': threshold,
+            'release': threshold,
+        }
+    )
+
+    s = storage.content_add(contents)
+    assert s == {}
+    s = storage.skipped_content_add(skipped_contents)
+    assert s == {}
+    s = storage.directory_add(directories)
+    assert s == {}
+    s = storage.revision_add(revisions)
+    assert s == {}
+    s = storage.release_add(releases)
+    assert s == {}
+
+    assert len(storage._objects['content']) == len(contents)
+    assert len(storage._objects['skipped_content']) == len(skipped_contents)
+    assert len(storage._objects['directory']) == len(directories)
+    assert len(storage._objects['revision']) == len(revisions)
+    assert len(storage._objects['release']) == len(releases)
+
+    # clear only content from the buffer
+    s = storage.clear_buffers(['content'])
+    assert s is None
+
+    # specific clear operation on specific object type content only touched
+    # them
+    assert len(storage._objects['content']) == 0
+    assert len(storage._objects['skipped_content']) == len(skipped_contents)
+    assert len(storage._objects['directory']) == len(directories)
+    assert len(storage._objects['revision']) == len(revisions)
+    assert len(storage._objects['release']) == len(releases)
+
+    # clear current buffer from all object types
+    s = storage.clear_buffers()
+    assert s is None
+
+    assert len(storage._objects['content']) == 0
+    assert len(storage._objects['skipped_content']) == 0
+    assert len(storage._objects['directory']) == 0
+    assert len(storage._objects['revision']) == 0
+    assert len(storage._objects['release']) == 0
diff --git a/swh/storage/validate.py b/swh/storage/validate.py
--- a/swh/storage/validate.py
+++ b/swh/storage/validate.py
@@ -5,7 +5,7 @@
 
 import datetime
 import contextlib
-from typing import Dict, Iterable, List
+from typing import Dict, Iterable, List, Optional
 
 from swh.model.model import (
     BaseModel, SkippedContent, Content, Directory, Revision, Release, Snapshot,
@@ -100,3 +100,9 @@
         with convert_validation_exceptions():
             origin = Origin.from_dict(origin)
         return self.storage.origin_add_one(origin)
+
+    def clear_buffers(
+            self, object_types: Optional[Iterable[str]] = None) -> None:
+        if hasattr(self.storage, 'clear_buffers'):
+            return self.storage.clear_buffers(object_types)
+        return None