How I can obtain a good cleaning in Aluminum Alloy 355-T71 Casting-Sand AMS 4214

We have a problems with the cleaning in some parts with this material Aluminum Alloy 355-T71 Casting-Sand AMS 4214 , somebody know a good chemical that we can use by to obtain a good cleaning and post to make a good anodizing

thanks a lot

1. Clean in any alkali that does not contain silicate and does not etch, even Grocery Store Dawn Detergent

2. Cold Water rinse

DO NOT ETCH IN ALKALI

3. 100% Nitric Acid plus 2 pounds per gallon ammonium bifluoride, about 20 to 30 seconds until the metal turns frothy white all over

4 & 5, two quick rinses, do not stop to look

6. Anodize.

This process is detailed in the newly released Aluminio El Como.