I just put all the ingredients in a ziplock or plastic bag, add seasoning, shake it up to mix, then drizzle oil into the bag, and shake it up again to mix all together. Then pour everything onto a sheet pan, and spread out the ingredients. If there is extra oil/seasoning left in the bag, you can pour it over the ingredients in the pan.  I think it can cut down the amount of oil and seasoning, but I usually just sprinkle on more seasoning. I have **never** had any problems with cutting back on the oil. As long as everything is well coated, it cooks well, and I don't get extra oil pooling on the sheet pan.
You don't have anything extra to wash; just throw out the plastic bag.