diff --git a/lib/6to5/transformation/transform.js b/lib/6to5/transformation/transform.js
index 981a341d6b..7a5a36fa77 100644
--- a/lib/6to5/transformation/transform.js
+++ b/lib/6to5/transformation/transform.js
@@ -39,10 +39,6 @@ transform.moduleFormatters = {
 };
 
 _.each({
-  // spec
-  specBlockHoistFunctions:   require("./transformers/spec-block-hoist-functions"),
-  specNoForInOfAssignment:   require("./transformers/spec-no-for-in-of-assignment"),
-
   // playground
   methodBinding:             require("./transformers/playground-method-binding"),
   memoizationOperator:       require("./transformers/playground-memoization-operator"),
diff --git a/lib/6to5/transformation/transformers/spec-block-hoist-functions.js b/lib/6to5/transformation/transformers/spec-block-hoist-functions.js
deleted file mode 100644
index 8d18464de0..0000000000
--- a/lib/6to5/transformation/transformers/spec-block-hoist-functions.js
+++ /dev/null
@@ -1,18 +0,0 @@
-var t = require("../../types");
-
-exports.BlockStatement = function (node, parent) {
-  if (t.isFunction(parent)) return;
-
-  node.body = node.body.map(function (node) {
-    if (t.isFunction(node)) {
-      node.type = "FunctionExpression";
-      var declar = t.variableDeclaration("let", [
-        t.variableDeclarator(node.id, node)
-      ]);
-      declar._blockHoist = true;
-      return declar;
-    } else {
-      return node;
-    }
-  });
-};
diff --git a/lib/6to5/transformation/transformers/spec-no-for-in-of-assignment.js b/lib/6to5/transformation/transformers/spec-no-for-in-of-assignment.js
deleted file mode 100644
index 5af12108f1..0000000000
--- a/lib/6to5/transformation/transformers/spec-no-for-in-of-assignment.js
+++ /dev/null
@@ -1,10 +0,0 @@
-var t = require("../../types");
-
-exports.ForInStatement =
-exports.ForOfStatement = function (node, parent, file) {
-  var left = node.left;
-  if (t.isVariableDeclaration(left)) {
-    var declar = left.declarations[0];
-    if (declar.init) throw file.errorWithNode(declar, "No assignments allowed in for-in/of head");
-  }
-};