I know this sounds backwards for a game like this, but I wish there was a power-washer trailer a scout car or etc could pull to your garage which could spray off vehicles to make them clean.
I like "getting dirty" but I wish I could start new tasks/objectives with a clean truck and see how much each goal collects on the paint before washing it again.
Something akin to the farm sim games.
Just wanted to toss the suggestion out there for the devs,
--Holy