You can use a quality wood preservative on the wood slats, and if the trailer is aluminum it will not rust. Here is the 18' tilt bed H&H trailer I use to trailer the ATVs, motorcycles, muscle car, and Jeep. Its only a year old, but so far it looks as good as it did right after I applied the Penafin wood preservative, which in this case was Brazilian Rose Wood Oil, specifically for pressure treated wood.
