See the quickest way to remove tarnished aluminum build up from the top sides of your trailer by using steel wool and Mothers aluminum polish. I also added a thermal roll on silicone to stop the stains that get created on the aluminum and outer wall. the other reason I added 2 coats to the roof was to lower heat / UV rays from heating the trailer during the summer.
About 15 years ago I converted my 14 foot cargo trailer into a toy hauler by adding AC, refrigerator, counter, overhead console with radio and speakers, cabinets for storage and lights under the console and along the upper walls.
It allows me to still use the trailer for projects but I can still roll the 4 wheeler into it, role it out, roll out 2 black carpets and blow up to thick air mattresses and a fold out table. One mattress across the back wall and one on the side wall leaves plenty of walkway.
I put a multi plug adapter on the front wall to tied into 110 for an electric heater, microwave etc... and the lighting and radio are on 12 volt.
I am debating on putting in the gray garage epoxy with sprinkles just to spruce it up a little more. I have had this trailer for at least 15 years and use it at the deer lease, camping trips, motocross trips, moving odds and ins and for gathering materials for home repair and have to admit it has held up very well over the years. Thanks for looking, hope this was helpful and gives you some ideas.