diff --git a/config.json b/config.json
index 8d84db1bb4..a2f06e1159 100644
--- a/config.json
+++ b/config.json
@@ -1155,9 +1155,7 @@
         "name": "Binary",
         "uuid": "29c3c9ff-c7f3-4646-9612-7cd768d237ab",
         "prerequisites": [],
-        "practices": [
-          "tail-call-recursion"
-        ],
+        "practices": [],
         "difficulty": 3,
         "status": "deprecated"
       },
@@ -1309,9 +1307,7 @@
         "name": "Hexadecimal",
         "uuid": "8154a099-5d6f-4e71-83fe-45ab23475778",
         "prerequisites": [],
-        "practices": [
-          "charlists"
-        ],
+        "practices": [],
         "difficulty": 3,
         "status": "deprecated"
       },