diff --git a/src/ctlssa/suggestions/logic/domains.py b/src/ctlssa/suggestions/logic/domains.py
index dbd4d05..f1d2f4d 100644
--- a/src/ctlssa/suggestions/logic/domains.py
+++ b/src/ctlssa/suggestions/logic/domains.py
@@ -87,13 +87,21 @@ def __init__(self):
         self.new_data = []
         self.auto_write_batch_size = settings.AUTO_WRITE_BATCH_SIZE
 
+    def clean_domain(self, domain: str) -> str:
+        # some normalization as a data source might be polluted, merklemap is and there might be an off-day in ct too
+        domain = domain.lower().strip()
+
+        # some domains end with a dot, because DNS entries are stored like this. This is a slight leak/pollution in the
+        # dataset from merklemap.
+        return domain.removesuffix(".")
+
     def add_domain(self, domain: str, processing_date: date):
         # wildcards do not exist in the hostname field, so no need to filter.
 
-        # some normalization as a data source might be polluted, merklemap is and there might be an off-day in ct too
-        domain = domain.lower().strip()
+        domain = self.clean_domain(domain)
 
         # we can use this shortcut as there are no two level top level domains in the dutch zones
+        # this approach will fall apart in case of .co.uk domains
         # the partition method is the fastest:
         rest, delimiter, suffix = domain.rpartition(".")
         subdomain, delimiter, domain = rest.rpartition(".")
diff --git a/tests/test_ingest.py b/tests/test_ingest.py
index e93de65..b80e004 100644
--- a/tests/test_ingest.py
+++ b/tests/test_ingest.py
@@ -1,3 +1,4 @@
+from ctlssa.suggestions.logic.domains import CaseOptimizedBulkInsert
 from ctlssa.suggestions.logic.ingest import add_domains, certstream_callback
 from ctlssa.suggestions.models import Domain
 
@@ -159,3 +160,15 @@ def test_add_domains(db, caplog):  # sourcery skip: extract-duplicate-method
 
     # test if logging works correctly, disabled due to flooding
     # assert "ingesting" in caplog.text
+
+
+def test_merklemap_clean_domain():
+
+    cobi = CaseOptimizedBulkInsert()
+
+    # test removal of last dot in polluted data
+    assert cobi.clean_domain("test.nu.nl.") == "test.nu.nl"
+    assert cobi.clean_domain("test.nu.nl") == "test.nu.nl"
+
+    # test case and padding removal
+    assert cobi.clean_domain(" TEST.nu.nl  ") == "test.nu.nl"