Ramona said..
To remove all the paint use paint stripper and scrape with a wooden or plastic scraper. To clean off all the corrosion I use a product called Metal Gleam. It leaves aluminium dead clean and etched ready for paint. If you are going to paint, do it immediately the aluminium dries after rinsing off the acid.
The Metal Gleam probably has hydroflouric acid in it which concentrated is scary stuff. Fairly benign if well diluted. Another similar product is Ally Bright.
