diff --git a/dlslime-ctrl/src/redis_repo.rs b/dlslime-ctrl/src/redis_repo.rs
index 25b04e76..142b8a3e 100644
--- a/dlslime-ctrl/src/redis_repo.rs
+++ b/dlslime-ctrl/src/redis_repo.rs
@@ -283,7 +283,14 @@ impl RedisRepo {
             }
         }
 
-        // 5. Delete inbox
+        // 5. Delete mailbox streams/inbox
+        let stream_key = self.scoped_key(scope, &["stream", agent_name]);
+        redis::cmd("DEL")
+            .arg(&stream_key)
+            .query_async::<()>(&mut *conn)
+            .await
+            .ok();
+
         let inbox_key = self.scoped_key(scope, &["inbox", agent_name]);
         redis::cmd("DEL")
             .arg(&inbox_key)
diff --git a/dlslime/dlslime/peer_agent/_agent.py b/dlslime/dlslime/peer_agent/_agent.py
index d63792a6..e4abbcb3 100644
--- a/dlslime/dlslime/peer_agent/_agent.py
+++ b/dlslime/dlslime/peer_agent/_agent.py
@@ -200,6 +200,7 @@ def __init__(
 
         # Build Redis key prefix from scope parameter
         self._redis_key_prefix = scope or ""
+        self._session_started_at = time.time()
 
         # NanoCtrl HTTP client
         self._client = NanoCtrlClient(ctrl_url, scope=self._redis_key_prefix or None)
@@ -670,6 +671,7 @@ def _cleanup_stale_exchange_keys(self) -> None:
         patterns = [
             f"{prefix}exchange:{self.alias}:*",
             f"{prefix}exchange:*:{self.alias}",
+            f"{prefix}exchange:*:{self.alias}:*",
         ]
         try:
             keys_to_delete: list[str] = []
diff --git a/dlslime/dlslime/peer_agent/_mailbox.py b/dlslime/dlslime/peer_agent/_mailbox.py
index 63caa9d1..accaf216 100644
--- a/dlslime/dlslime/peer_agent/_mailbox.py
+++ b/dlslime/dlslime/peer_agent/_mailbox.py
@@ -63,10 +63,10 @@ def start(self) -> None:
         # so losing the message stalls the handshake forever.
         #
         # Instead, _listen_loop reads from "0-0" and processes every message
-        # on the stream. Truly stale messages from a prior crashed session
-        # with the same alias fail endpoint.connect at handshake time — the
-        # listen loop catches that and continues, so later in-flight qp_ready
-        # from the current peer session still completes the handshake.
+        # on the stream. Stale messages must be removed when the previous
+        # agent incarnation is cleaned up. Do not use local wall-clock
+        # timestamps here: a valid early qp_ready can predate this listener,
+        # and sender/receiver clocks may drift across nodes.
         self._thread = threading.Thread(target=self._listen_loop, daemon=True)
         self._thread.start()
         logger.info(
@@ -316,7 +316,6 @@ def _try_connect_peer_inner(
                         "peer": self._agent.alias,
                         "qp_info": json.dumps(my_qp_info, default=str),
                         "conn_meta": json.dumps(my_conn_meta, default=str),
-                        "timestamp": str(time.time()),
                     },
                     maxlen=1000,
                     approximate=True,