OK, first off, please keep in mind this is what worked for me - it may not work for you. This information is to be used at your own risk - if you destroy your B&O using these directions, it is your own fault. OK, now that that unpleasantness is over:

Products used:

2000 grit wet type sandpaper

1000 grit wet type sandpaper

90% Isopropal Alcohol

Water

Eagle One Mag & Aluminum Wheel Polish Part #1030605

Turtle Wax Automotive Rubbing Compound

Three clean, soft cloths

If you have deep scratches, first use the 1000 grip sandpaper and some water - wet it before using to keep the grit clean and keep it from cutting too deeply. Work in a motion along the longest axis - for example, with my BL 500 hanging on the wall, I worked up and down. A BC 9500 would be worked side-to-side.

After this, (or if you have light scratches) follow with the 2000 grit wet paper- again with water. This is followed by the Eagle One polish - be careful; this product is aggressive and will create a bright shine. If your product is not shiny (the BL 5000s are not, they have a more satin finish). Just polish a little bit at a time, wipe it down (with a clean, soft cloth) and check to see if it needs more. If it is too shiny, I was able to dull it  a bit with the Rubbing Compound.

A few strokes with the Polish will clean the parts without polishing them if they are just dirty.

After the above, polish with a very soft cloth, followed by a rub down with a small amount of the alcohol on a clean cloth to remove any residue and fingerprints.

Above all BE CAREFUL. Do just a little at a time as these products can damage the surface if you are not careful. 

This is a very time consuming project. Just doing the two BL 5000s took 3 hours, and they were really not that bad. I could spend a few more if I wanted them to look like new.

Hope that helps!