My neighbor lost the dust cap for his trailer just before he was heading out on a trip. He tried to find a replacement cap but needed a non standard size that required a special order. He came over to see if I had anything in my shop that might work. The solution ended up being a cut off metal pop can with a clamp around the hub. While this is right from the “yes I did grow up on the farm, why do you ask?” department, it is a quick fix for anyone finding themselves in a similar need for a quick temporary dust cap.