Brightening process for aluminium required

Does anyone know of a brightening process (that works) for brightening aluminium prior to anodizing that does not liberate nitrous oxide fumes?

Processes liberating nitrous oxide fumes have to be registered when operated in the UK. This also involves buying expensive equipment to scrub the fumes, keeping records and generally being overseen by a local authority. I am sure that the USA and other countries have a similar arrangement.

Any information will be gratefully received.

There are ready mixed solutions available but we make a standard Phosphoric acid based bright dip for Aluminum. We have also electropolished 6061 aluminum parts to a near mirror finish for special applications.