I purchased a set of decals recently. i cleaned the surface with alcohol. I let it set for about two hours ,to be sure the alcohol was gone. I put them on my plastic gas tank. after about two months the decal has bubbled on both sides. I pulled them off and they smell like gas. on the sticky side. Could gas fumes be seeping out through the sides and causing the problem? Can the gas tank be sealed with tank sealer inside like a metal tank?