diff --git a/index.js b/index.js
index f384b3c..bdc5177 100644
--- a/index.js
+++ b/index.js
@@ -1,30 +1,23 @@
 var vm = require('vm')
 
-function clearContext () {
-  // eslint-disable-next-line no-global-assign
-  Function = undefined
-  const keys = Object.getOwnPropertyNames(this).concat(['constructor'])
-  keys.forEach((key) => {
-    const item = this[key]
-    if (!item) return
-    if (typeof Object.getPrototypeOf(item).constructor === 'function') {
-      Object.getPrototypeOf(item).constructor = undefined
-    }
-    if (typeof item.constructor === 'function') {
-      this[key].constructor = undefined
-    }
-  })
-}
-
 module.exports = function safeEval (code, context, opts) {
   var sandbox = {}
   var resultKey = 'SAFE_EVAL_' + Math.floor(Math.random() * 1000000)
   sandbox[resultKey] = {}
-  var clearContextCall = `(${clearContext.toString()})();`
-  code = `${clearContextCall}${resultKey}=${code}`
+  var clearContext = `
+    (function() {
+      Function = undefined;
+      const keys = Object.getOwnPropertyNames(this).concat(['constructor']);
+      keys.forEach((key) => {
+        const item = this[key];
+        if (!item || typeof item.constructor !== 'function') return;
+        this[key].constructor = undefined;
+      });
+    })();
+  `
+  code = clearContext + resultKey + '=' + code
   if (context) {
     Object.keys(context).forEach(function (key) {
-      if (context[key] === Function) return
       sandbox[key] = context[key]
     })
   }
diff --git a/package.json b/package.json
index aaacf93..55327b4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "safe-eval",
-  "version": "0.4.2",
+  "version": "0.4.1",
   "description": "Safer version of eval()",
   "main": "index.js",
   "scripts": {
diff --git a/test/test.js b/test/test.js
index 43670da..c79027b 100644
--- a/test/test.js
+++ b/test/test.js
@@ -44,33 +44,7 @@ describe('safe-eval', function () {
     })
   })
 
-  it('should not have access to Node.js objects using context (CWE-265)', function () {
-    var code = 'test(\'return process\')()'
-    assert.throws(function () {
-      safeEval(code, {
-        // eslint-disable-next-line no-new-func
-        test: new Function().constructor
-      })
-    })
-  })
-
-  it('should not have access to Node.js objects using Object.getPrototypeOf (CWE-265)', function () {
-    var code = `Object.getPrototypeOf(Object).constructor('return process')();`
-    assert.throws(function () {
-      safeEval(code)
-    })
-  })
-
-  it('should not have access to Node.js objects using Object.getPrototypeOf with context (CWE-265)', function () {
-    var code = `Object.getPrototypeOf(obj).constructor.constructor("return process")();`
-    assert.throws(function () {
-      safeEval(code, {
-        obj: Object
-      })
-    })
-  })
-
-  it('should not have access to Node.js objects using this.constructor (CWE-265)', function () {
+  it('should not have access to Node.js objects (CWE-265)', function () {
     var code = 'this.constructor.constructor(\'return process\')()'
     assert.throws(function () {
       safeEval(code)