diff --git a/librarian/discord/cogs/background/github.py b/librarian/discord/cogs/background/github.py
index ad63665..5bea33d 100644
--- a/librarian/discord/cogs/background/github.py
+++ b/librarian/discord/cogs/background/github.py
@@ -274,6 +274,7 @@ async def sort_for_updates(self, pulls: typing.List[storage.models.pull.Pull]) -
     async def handle_update_exception(self, exc: errors.LibrarianException, item: typing.Tuple[int, int]):
         if isinstance(exc, errors.NoDiscordChannel):
             await self.bot.settings.reset(exc.channel_id)
+            self.storage.discord.delete_channel_messages(exc.channel_id)
 
     async def status(self) -> dict:
         # FIXME: make something useful here
diff --git a/librarian/storage/models/discord.py b/librarian/storage/models/discord.py
index dfdd125..4b9656c 100644
--- a/librarian/storage/models/discord.py
+++ b/librarian/storage/models/discord.py
@@ -90,6 +90,12 @@ def delete_message(self, message_id, channel_id, s):
             DiscordMessage.channel_id == channel_id,
         ).delete()
 
+    @utils.optional_session
+    def delete_channel_messages(self, channel_id, s) -> int:
+        return s.query(DiscordMessage).filter(
+            DiscordMessage.channel_id == channel_id,
+        ).delete()
+
     @utils.optional_session
     def messages_by_pull_numbers(self, *pull_numbers: typing.List[int], s: orm.Session = None):
         """ Return all known messages that are tied to the specified pulls. """
diff --git a/tests/discord/cogs/background/test_github.py b/tests/discord/cogs/background/test_github.py
index bab2ecb..5d46ac8 100644
--- a/tests/discord/cogs/background/test_github.py
+++ b/tests/discord/cogs/background/test_github.py
@@ -265,8 +265,10 @@ async def test__exception_handling_no_channel(
         response = collections.namedtuple("Response", "status reason")(404, "testing stuff")
         client.fetch_channel = mocker.AsyncMock(side_effect=discord_errors.NotFound(response, "error"))
         client.settings.reset = mocker.AsyncMock()
+        client.storage.discord.delete_channel_messages = mocker.Mock()
         await monitor.sort_for_updates([pp])
 
         client.settings.reset.assert_called()
+        client.storage.discord.delete_channel_messages.assert_called()
         args, _ = client.settings.reset.call_args
         assert args == (123,)
diff --git a/tests/storage/models/test_discord.py b/tests/storage/models/test_discord.py
index 9fe49b7..c66cb67 100644
--- a/tests/storage/models/test_discord.py
+++ b/tests/storage/models/test_discord.py
@@ -30,6 +30,22 @@ def test__delete_message(self, storage, existing_pulls):
         storage.discord.delete_message(123, 456)
         assert not storage.discord.messages_by_pull_numbers(789)
 
+    def test__delete_channel_messages(self, storage, existing_pulls):
+        assert storage.discord.delete_channel_messages(123) == 0
+        storage.discord.save_messages(*(
+            stg.DiscordMessage(
+                id=i,
+                channel_id=123,
+                pull_number=1
+            )
+            for i in range(10)
+        ))
+        storage.discord.save_messages(stg.DiscordMessage(id=15, channel_id=124, pull_number=1))
+
+        assert len(storage.discord.messages_by_pull_numbers(1)) == 11
+        assert storage.discord.delete_channel_messages(123) == 10
+        assert len(storage.discord.messages_by_pull_numbers(1)) == 1
+
 
 class TestDiscordUsers:
     def test__promote_one(self, storage):