diff --git a/cli/rt/01_web_util.js b/cli/rt/01_web_util.js
index ee8992eb25..4a3df65cea 100644
--- a/cli/rt/01_web_util.js
+++ b/cli/rt/01_web_util.js
@@ -3,10 +3,6 @@
 ((window) => {
   const illegalConstructorKey = Symbol("illegalConstructorKey");
 
-  function isInvalidDate(x) {
-    return isNaN(x.getTime());
-  }
-
   function requiredArguments(
     name,
     length,
@@ -20,25 +16,6 @@
     }
   }
 
-  function immutableDefine(
-    o,
-    p,
-    value,
-  ) {
-    Object.defineProperty(o, p, {
-      value,
-      configurable: false,
-      writable: false,
-    });
-  }
-
-  function hasOwnProperty(obj, v) {
-    if (obj == null) {
-      return false;
-    }
-    return Object.prototype.hasOwnProperty.call(obj, v);
-  }
-
   const objectCloneMemo = new WeakMap();
 
   function cloneArrayBuffer(
@@ -136,24 +113,9 @@
     }
   }
 
-  /** A helper function which ensures accessors are enumerable, as they normally
- * are not. */
-  function defineEnumerableProps(
-    Ctor,
-    props,
-  ) {
-    for (const prop of props) {
-      Reflect.defineProperty(Ctor.prototype, prop, { enumerable: true });
-    }
-  }
-
   window.__bootstrap.webUtil = {
     illegalConstructorKey,
-    isInvalidDate,
     requiredArguments,
-    immutableDefine,
-    hasOwnProperty,
     cloneValue,
-    defineEnumerableProps,
   };
 })(this);
diff --git a/cli/rt/02_console.js b/cli/rt/02_console.js
index ab91ffc099..43638efedf 100644
--- a/cli/rt/02_console.js
+++ b/cli/rt/02_console.js
@@ -14,10 +14,16 @@
     bold,
   } = window.__bootstrap.colors;
 
-  const {
-    isInvalidDate,
-    hasOwnProperty,
-  } = window.__bootstrap.webUtil;
+  function isInvalidDate(x) {
+    return isNaN(x.getTime());
+  }
+
+  function hasOwnProperty(obj, v) {
+    if (obj == null) {
+      return false;
+    }
+    return Object.prototype.hasOwnProperty.call(obj, v);
+  }
 
   // Copyright Joyent, Inc. and other Node contributors. MIT license.
   // Forked from Node's lib/internal/cli_table.js
diff --git a/cli/rt/06_util.js b/cli/rt/06_util.js
index 011fa6de5c..f4804c519a 100644
--- a/cli/rt/06_util.js
+++ b/cli/rt/06_util.js
@@ -46,10 +46,6 @@
     return promise;
   }
 
-  function notImplemented() {
-    throw new Error("not implemented");
-  }
-
   function immutableDefine(
     o,
     p,
@@ -139,7 +135,6 @@
   window.__bootstrap.util = {
     log,
     setLogDebug,
-    notImplemented,
     createResolvable,
     assert,
     AssertionError,
diff --git a/cli/tsc/00_bootstrap_namespace.js b/cli/tsc/00_bootstrap_namespace.js
deleted file mode 100644
index bccbc09c10..0000000000
--- a/cli/tsc/00_bootstrap_namespace.js
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-
-// The only purpose of this file is to set up "globalThis.__bootstrap" namespace,
-// that is used by scripts in this directory to reference exports between
-// the files.
-
-// This namespace is removed during runtime bootstrapping process.
-
-globalThis.__bootstrap = {};
diff --git a/cli/tsc/01_errors.js b/cli/tsc/01_errors.js
deleted file mode 100644
index fb2bb78c27..0000000000
--- a/cli/tsc/01_errors.js
+++ /dev/null
@@ -1,154 +0,0 @@
-// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-
-((window) => {
-  class NotFound extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "NotFound";
-    }
-  }
-
-  class PermissionDenied extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "PermissionDenied";
-    }
-  }
-
-  class ConnectionRefused extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "ConnectionRefused";
-    }
-  }
-
-  class ConnectionReset extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "ConnectionReset";
-    }
-  }
-
-  class ConnectionAborted extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "ConnectionAborted";
-    }
-  }
-
-  class NotConnected extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "NotConnected";
-    }
-  }
-
-  class AddrInUse extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "AddrInUse";
-    }
-  }
-
-  class AddrNotAvailable extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "AddrNotAvailable";
-    }
-  }
-
-  class BrokenPipe extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "BrokenPipe";
-    }
-  }
-
-  class AlreadyExists extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "AlreadyExists";
-    }
-  }
-
-  class InvalidData extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "InvalidData";
-    }
-  }
-
-  class TimedOut extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "TimedOut";
-    }
-  }
-
-  class Interrupted extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "Interrupted";
-    }
-  }
-
-  class WriteZero extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "WriteZero";
-    }
-  }
-
-  class UnexpectedEof extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "UnexpectedEof";
-    }
-  }
-
-  class BadResource extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "BadResource";
-    }
-  }
-
-  class Http extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "Http";
-    }
-  }
-
-  class Busy extends Error {
-    constructor(msg) {
-      super(msg);
-      this.name = "Busy";
-    }
-  }
-
-  const errors = {
-    NotFound,
-    PermissionDenied,
-    ConnectionRefused,
-    ConnectionReset,
-    ConnectionAborted,
-    NotConnected,
-    AddrInUse,
-    AddrNotAvailable,
-    BrokenPipe,
-    AlreadyExists,
-    InvalidData,
-    TimedOut,
-    Interrupted,
-    WriteZero,
-    UnexpectedEof,
-    BadResource,
-    Http,
-    Busy,
-  };
-
-  window.__bootstrap.errors = {
-    errors,
-  };
-})(this);
diff --git a/cli/tsc/99_main_compiler.js b/cli/tsc/99_main_compiler.js
index d06912b1f4..a6989381d1 100644
--- a/cli/tsc/99_main_compiler.js
+++ b/cli/tsc/99_main_compiler.js
@@ -18,7 +18,6 @@ delete Object.prototype.__proto__;
 
 ((window) => {
   const core = window.Deno.core;
-  const errors = window.__bootstrap.errors.errors;
 
   let logDebug = false;
   let logSource = "JS";
@@ -1345,28 +1344,6 @@ delete Object.prototype.__proto__;
       throw new Error("Worker runtime already bootstrapped");
     }
     hasBootstrapped = true;
-    core.registerErrorClass("NotFound", errors.NotFound);
-    core.registerErrorClass("PermissionDenied", errors.PermissionDenied);
-    core.registerErrorClass("ConnectionRefused", errors.ConnectionRefused);
-    core.registerErrorClass("ConnectionReset", errors.ConnectionReset);
-    core.registerErrorClass("ConnectionAborted", errors.ConnectionAborted);
-    core.registerErrorClass("NotConnected", errors.NotConnected);
-    core.registerErrorClass("AddrInUse", errors.AddrInUse);
-    core.registerErrorClass("AddrNotAvailable", errors.AddrNotAvailable);
-    core.registerErrorClass("BrokenPipe", errors.BrokenPipe);
-    core.registerErrorClass("AlreadyExists", errors.AlreadyExists);
-    core.registerErrorClass("InvalidData", errors.InvalidData);
-    core.registerErrorClass("TimedOut", errors.TimedOut);
-    core.registerErrorClass("Interrupted", errors.Interrupted);
-    core.registerErrorClass("WriteZero", errors.WriteZero);
-    core.registerErrorClass("UnexpectedEof", errors.UnexpectedEof);
-    core.registerErrorClass("BadResource", errors.BadResource);
-    core.registerErrorClass("Http", errors.Http);
-    core.registerErrorClass("URIError", URIError);
-    core.registerErrorClass("TypeError", TypeError);
-    core.registerErrorClass("Other", Error);
-    core.registerErrorClass("Busy", errors.Busy);
-    delete globalThis.__bootstrap;
     runtimeStart("TS");
   }