1) degrease the surface with petroleum ether

2) use deionized water (or boiled and cooled eventually) to wet the surface and soak decal

3) put the decal to the water and wait until the paper underneath soak

4) put a decal on the wetted surface and slide it on this surface.

5) squeeze the water out with soft cloth of graphics from the center to the outer edges.

6) wait about 24 hours until the water evaporates and gently peel off the transport foil from the decal (the evaporating process can be accelerated by heating with the hair dryer). After that - use a hairdryer again for sure.