If you can't do a media blast, you can do a good cleaning with S100 with a lot of attention to nooks and crannies using sponges, tooth brushes, Q-Tips, and Scotchbrite. You might have to hit some really greasy spots twice. S100 kicks a$$ and will get all the grease and oil off. Follow this with a wipe using rubbing alcohol and a lot of clean paper towels.
Any aluminum corrosion can be cleaned up with NAPA Aluminum Brightener and Scotchbrite. follow the direction on the bottle.
Mask and shoot a couple light coats of Etching Primer. For all those bare aluminum stripes I cut strips of masking tape by putting the tape on a sheet of glass and cutting narrow strips with a new razor blade and a steel straight edge. You can also see if you can get 3M Fine Line tape in the right width.
A couple thin coats of a black base coat until you have good coverage. Then pull the masking tape off the lines and shoot a couple coats of 2K rattle can Matte Clear Coat. Let the clear coat cure for as long as possible before handling it. I have found that it can take up to a week or more to get really hard in cool weather. I use USC 3680065 Spray MAX 2K Matte Finish Aerosol Clear Coat. Not cheap, but it is easy to use and gets good results.
