diff --git a/51.md b/51.md
index 47ed8991..95190414 100644
--- a/51.md
+++ b/51.md
@@ -32,6 +32,8 @@ For example, _mute lists_ can contain the public keys of spammers and bad actors
 | Interests      | 10015 | topics a user may be interested in and pointers             | `"t"` (hashtags) and `"a" (kind:30015 interest set)`                              |
 | Emojis         | 10030 | user preferred emojis and pointers to emoji sets            | `"emoji"` (see [NIP-30](30.md)) and `"a"` (kind:30030 emoji set)                  |
 
+Mute list (kind:10000) can contain an optional timestamp for each tag, indicating when that given mute item should expire. Clients SHOULD ignore tags where the current timestamp is greater than the expiration timestamp. If no expiration timestamp is provided, clients SHOULD assume the mute item is indefinite (until a more recent mute list is relayed).
+
 ## Sets
 
 Sets are lists with well-defined meaning that can enhance the functionality and the UI of clients that rely on them. Unlike standard lists, users are expected to have more than one set of each kind, therefore each of them must be assigned a different `"d"` identifier.
@@ -80,6 +82,23 @@ Some clients have used these lists in the past, but they should work on transiti
 }
 ```
 
+### A _mute list_ with the items expiring on January 1st 2025 00:00 UTC
+
+```json
+{
+  "id": "a92a316b75e44cfdc19986c634049158d4206fcc0b7b9c7ccbcdabe28beebcd0",
+  "pubkey": "854043ae8f1f97430ca8c1f1a090bdde6488bd5115c7a45307a2a212750ae4cb",
+  "created_at": 1699597889,
+  "kind": 10000,
+  "tags": [
+    ["p", "07caba282f76441955b695551c3c5c742e5b9202a3784780f8086fdcdc1da3a9", "1735689600"],
+    ["p", "a55c15f5e41d5aebd236eca5e0142789c5385703f1a7485aa4b38d94fd18dcc4", "1735689600"]
+  ],
+  "content": "",
+  "sig": "1173822c53261f8cffe7efbf43ba4a97a9198b3e402c2a1df130f42a8985a2d0d3430f4de350db184141e45ca844ab4e5364ea80f11d720e36357e1853dba6ca"
+}
+```
+
 ### A _curation set_ of articles and notes about yaks
 
 ```