Yes,if the stickers are good,a bath in lukewarm water and dish soap will make them nice.Let the vehicle soak in the sink for several hours,and don't scrub it unless you have to.

Rinse it in cold water and let it dry on paper towels for several hours.

You can also use Oxy-Clean.

If it has mold or anything that might be dangerous,you'll have to use bleach.Take all safety precautions.

JoeCustoms has a great article on cleaning toys:Cleaning Vehicles and Playsets