how do i change the color of a menu in a custom toolbar?

(first way) in your style :

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
    ...
    <item name="actionOverflowButtonStyle">@style/MyOverflowButtonStyle</item>
</style>

<style name="MyOverflowButtonStyle" parent="Widget.AppCompat.ActionButton.Overflow">
    <item name="android:tint">#62ff00</item>
</style>

Or you can change it with toolbar style like this:

<android.support.v7.widget.Toolbar
  ...
  theme="@style/MyToolbarStyle"
/>

and in your style:

<style name="MyToolbarStyle" parent="ThemeOverlay.AppCompat.ActionBar">
  <item name="android:textColorSecondary">#333333</item>
</style>