diff --git a/runbot/models/build_error.py b/runbot/models/build_error.py
index 1a1abeaf..a9b9acca 100644
--- a/runbot/models/build_error.py
+++ b/runbot/models/build_error.py
@@ -63,7 +63,7 @@ class BuildError(models.Model):
         cleaners = self.env['runbot.error.regex'].search([('re_type', '=', 'cleaning')])
         for vals in vals_list:
             content = vals.get('content')
-            cleaned_content = cleaners._r_sub('%', content)
+            cleaned_content = cleaners._r_sub(content)
             vals.update({
                 'cleaned_content': cleaned_content,
                 'fingerprint': self._digest(cleaned_content)
@@ -170,7 +170,7 @@ class BuildError(models.Model):
         for log in ir_logs:
             if search_regs._r_search(log.message):
                 continue
-            fingerprint = self._digest(cleaning_regs._r_sub('%', log.message))
+            fingerprint = self._digest(cleaning_regs._r_sub(log.message))
             hash_dict[fingerprint] |= log
 
         build_errors = self.env['runbot.build.error']
@@ -292,7 +292,7 @@ class BuildError(models.Model):
         changed_fingerprints = set()
         for build_error in self:
             fingerprint_before = build_error.fingerprint
-            build_error.cleaned_content = cleaning_regs._r_sub('%', build_error.content)
+            build_error.cleaned_content = cleaning_regs._r_sub(build_error.content)
             if fingerprint_before != build_error.fingerprint:
                 changed_fingerprints.add(build_error.fingerprint)
 
@@ -334,11 +334,12 @@ class ErrorRegex(models.Model):
     regex = fields.Char('Regular expression')
     re_type = fields.Selection([('filter', 'Filter out'), ('cleaning', 'Cleaning')], string="Regex type")
     sequence = fields.Integer('Sequence', default=100)
+    replacement = fields.Char('Replacement string', help="String used as a replacment in cleaning. '%' if not set")
 
-    def _r_sub(self, replace, s):
-        """ replaces patterns from the recordset by replace in the given string """
+    def _r_sub(self, s):
+        """ replaces patterns from the recordset by replacement's or '%' in the given string """
         for c in self:
-            s = re.sub(c.regex, '%', s)
+            s = re.sub(c.regex, c.replacement or '%', s)
         return s
 
     def _r_search(self, s):
diff --git a/runbot/models/ir_logging.py b/runbot/models/ir_logging.py
index cd59c015..c88140c3 100644
--- a/runbot/models/ir_logging.py
+++ b/runbot/models/ir_logging.py
@@ -55,7 +55,7 @@ class IrLogging(models.Model):
         for ir_logging in self:
             ir_logging.error_id = False
             if ir_logging.level in ('ERROR', 'CRITICAL', 'WARNING') and ir_logging.type == 'server':
-                fingerprints[self.env['runbot.build.error']._digest(cleaning_regexes._r_sub('%', ir_logging.message))].append(ir_logging)
+                fingerprints[self.env['runbot.build.error']._digest(cleaning_regexes._r_sub(ir_logging.message))].append(ir_logging)
         for build_error in self.env['runbot.build.error'].search([('fingerprint', 'in', list(fingerprints.keys()))], order='active asc'):
             for ir_logging in fingerprints[build_error.fingerprint]:
                 ir_logging.error_id = build_error.id
diff --git a/runbot/tests/test_build_error.py b/runbot/tests/test_build_error.py
index 4cda4709..3bf0c7bd 100644
--- a/runbot/tests/test_build_error.py
+++ b/runbot/tests/test_build_error.py
@@ -113,7 +113,10 @@ class TestBuildError(RunbotCase):
         ko_build = self.create_test_build({'local_result': 'ok', 'local_state': 'testing'})
         ok_build = self.create_test_build({'local_result': 'ok', 'local_state': 'running'})
 
-
+        cleaner = self.env['runbot.error.regex'].create({
+            'regex': '^FAIL: ',
+            're_type': 'cleaning',
+        })
 
         error_team = self.BuildErrorTeam.create({
             'name': 'test-error-team',
@@ -143,6 +146,8 @@ class TestBuildError(RunbotCase):
         ok_build._parse_logs()
         build_error = self.BuildError.search([('build_ids', 'in', [ko_build.id])])
         self.assertTrue(build_error)
+        self.assertTrue(build_error.fingerprint.startswith('af0e88f3'))
+        self.assertTrue(build_error.cleaned_content.startswith('%'), 'The cleaner should have replace "FAIL: " with a "%" sign by default')
         self.assertIn(ko_build, build_error.build_ids, 'The parsed build should be added to the runbot.build.error')
         self.assertFalse(self.BuildError.search([('build_ids', 'in', [ok_build.id])]), 'A successful build should not associated to a runbot.build.error')
         self.assertEqual(error_team, build_error.team_id)
diff --git a/runbot/views/build_error_views.xml b/runbot/views/build_error_views.xml
index dee52f78..23b82afe 100644
--- a/runbot/views/build_error_views.xml
+++ b/runbot/views/build_error_views.xml
@@ -221,6 +221,7 @@
               <group name="build_regex_group">
                 <field name="regex"/>
                 <field name="re_type"/>
+                <field name="replacement" attrs="{'invisible': [('re_type', '!=', 'cleaning')]}"/>
               </group>
             </sheet>
             <div class="oe_chatter">
@@ -239,6 +240,7 @@
                 <field name="sequence" widget="handle"/>
                 <field name="regex"/>
                 <field name="re_type"/>
+                <field name="replacement"/>
             </tree>
         </field>
     </record>