diff --git a/lib/6to5/generation/generators/methods.js b/lib/6to5/generation/generators/methods.js
index 341914c914..c812d0e808 100644
--- a/lib/6to5/generation/generators/methods.js
+++ b/lib/6to5/generation/generators/methods.js
@@ -3,8 +3,6 @@
 var t = require("../../types");
 
 exports._params = function (node, print) {
-  var self = this;
-
   this.push("(");
 
   print.join(node.params, {
diff --git a/lib/6to5/transformation/modules/_default.js b/lib/6to5/transformation/modules/_default.js
index 97c3a9fcb8..f2133a245a 100644
--- a/lib/6to5/transformation/modules/_default.js
+++ b/lib/6to5/transformation/modules/_default.js
@@ -223,7 +223,6 @@ DefaultFormatter.prototype.exportSpecifier = function (specifier, node, nodes) {
       // export * from "foo";
       nodes.push(this.buildExportsWildcard(ref, node));
     } else {
-      var ref;
       if (t.isSpecifierDefault(specifier) && !this.noInteropRequire) {
         // importing a default so we need to normalise it
         ref = t.callExpression(this.file.addHelper("interop-require"), [ref]);
diff --git a/lib/6to5/transformation/modules/common.js b/lib/6to5/transformation/modules/common.js
index 376e97eca2..122bf71f80 100644
--- a/lib/6to5/transformation/modules/common.js
+++ b/lib/6to5/transformation/modules/common.js
@@ -3,12 +3,10 @@
 module.exports = CommonJSFormatter;
 
 var DefaultFormatter = require("./_default");
-var traverse         = require("../../traverse");
 var util             = require("../../util");
 var t                = require("../../types");
 var _                = require("lodash");
 
-
 function CommonJSFormatter(file) {
   DefaultFormatter.apply(this, arguments);
 
diff --git a/lib/6to5/transformation/transformers/es6/parameters.default.js b/lib/6to5/transformation/transformers/es6/parameters.default.js
index c4b715fd85..9b08d6bed8 100644
--- a/lib/6to5/transformation/transformers/es6/parameters.default.js
+++ b/lib/6to5/transformation/transformers/es6/parameters.default.js
@@ -1,8 +1,7 @@
 "use strict";
 
-var traverse = require("../../../traverse");
-var util     = require("../../../util");
-var t        = require("../../../types");
+var util = require("../../../util");
+var t    = require("../../../types");
 
 var hasDefaults = function (node) {
   for (var i = 0; i < node.params.length; i++) {
@@ -11,7 +10,7 @@ var hasDefaults = function (node) {
   return false;
 };
 
-exports.Function = function (node, parent, scope, context, file) {
+exports.Function = function (node, parent, scope) {
   if (!hasDefaults(node)) return;
 
   t.ensureBlock(node);
@@ -35,7 +34,7 @@ exports.Function = function (node, parent, scope, context, file) {
     var left  = param.left;
     var right = param.right;
 
-    node.params[i] = scope.generateUidIdentifier("x")
+    node.params[i] = scope.generateUidIdentifier("x");
 
     // we're accessing a variable that's already defined within this function
     var localDeclar = scope.get(left.name, true);
diff --git a/lib/6to5/types/node.js b/lib/6to5/types/node.js
index 411fe40b26..0bea4da80e 100644
--- a/lib/6to5/types/node.js
+++ b/lib/6to5/types/node.js
@@ -1,7 +1,6 @@
 module.exports = Node;
 
-var object = require("../helpers/object");
-var acorn  = require("acorn-6to5");
+var acorn = require("acorn-6to5");
 
 var oldNode = acorn.Node;
 acorn.Node = Node;