Every month or two a thread shows up on here about cleaning and polishing a horse trailer.  Some specific products are usually recomened but I am wondering if there is really any difference between the painted alluminum skin many of us have on our trailers and a painted car?  Would the products used to wash and wax a car work on the painted alluminum?

Yes the painted surfaces can be treated the same.

Most of the question about washing trailers are directed at mill finish aluminum or other exposed aluminum surfaces.

Also horse trailers have more exposed hardware that allows for streaks to run down and across painted surfaces. i.e. window hinges, roof vents, ladders and hayracks. These create a different problem than a car where usually all the exposed surfaces are painted.