You can probably clean the vehicles carefully with a lightly damp sponge or rag, don't overdo it on the areas with stickers. Complete loose vehicles and figures with all their accessories and in nice condition sell best. The Cobra Night Raven jet, G.I. Joe Killer W.H.A.L.E. hovercraft, Cobra Moray Hydrofoil, and G.I. Joe Tomahawk helicopter are the best vehicles in your group.