Drill out vehicle rivets to release layers.

Fill jam jar with Dettol high enough to submerge the vehicle.

Place the parts with decals to remove in the jar ensuring all parts are submerged.

Seal the lid and allow to soak overnight 

Remove vehicle from jar and gently scrape off decals with the wooden skewer. Small areas can be selectively removed with the point of a cocktail stick (also useful for getting into recesses between body panels and other awkward areas). Larger areas can be removed with a wooden scraper, half a clothes peg is ideal for this.

If the decal is stubborn soak it again and repeat the process.