diff --git a/.internal/baseAssign.js b/.internal/baseAssign.js
deleted file mode 100644
index e27f12a3a..000000000
--- a/.internal/baseAssign.js
+++ /dev/null
@@ -1,17 +0,0 @@
-import copyObject from './copyObject.js'
-import keys from '../keys.js'
-
-/**
- * The base implementation of `assign` without support for multiple sources
- * or `customizer` functions.
- *
- * @private
- * @param {Object} object The destination object.
- * @param {Object} source The source object.
- * @returns {Object} Returns `object`.
- */
-function baseAssign(object, source) {
-  return object && copyObject(source, keys(source), object)
-}
-
-export default baseAssign
diff --git a/.internal/baseAssignIn.js b/.internal/baseAssignIn.js
deleted file mode 100644
index c4eb6e1bb..000000000
--- a/.internal/baseAssignIn.js
+++ /dev/null
@@ -1,17 +0,0 @@
-import copyObject from './copyObject.js'
-import keysIn from '../keysIn.js'
-
-/**
- * The base implementation of `assignIn` without support for multiple sources
- * or `customizer` functions.
- *
- * @private
- * @param {Object} object The destination object.
- * @param {Object} source The source object.
- * @returns {Object} Returns `object`.
- */
-function baseAssignIn(object, source) {
-  return object && copyObject(source, keysIn(source), object)
-}
-
-export default baseAssignIn
diff --git a/.internal/customDefaultsAssignIn.js b/.internal/customDefaultsAssignIn.js
deleted file mode 100644
index 5ff8e9a82..000000000
--- a/.internal/customDefaultsAssignIn.js
+++ /dev/null
@@ -1,29 +0,0 @@
-import eq from '../eq.js'
-
-/** Used for built-in method references. */
-const objectProto = Object.prototype
-
-/** Used to check objects for own properties. */
-const hasOwnProperty = objectProto.hasOwnProperty
-
-/**
- * Used by `defaults` to customize its `assignIn` use to assign properties
- * of source objects to the destination object for all destination properties
- * that resolve to `undefined`.
- *
- * @private
- * @param {*} objValue The destination value.
- * @param {*} srcValue The source value.
- * @param {string} key The key of the property to assign.
- * @param {Object} object The parent object of `objValue`.
- * @returns {*} Returns the value to assign.
- */
-function customDefaultsAssignIn(objValue, srcValue, key, object) {
-  if (objValue === undefined ||
-      (eq(objValue, objectProto[key]) && !hasOwnProperty.call(object, key))) {
-    return srcValue
-  }
-  return objValue
-}
-
-export default customDefaultsAssignIn