slowly begin peeling the chinstrap away from the chin, it should come off without much trouble, next slowly begin lifting the sides of the helmet away from the head(do not hold it open), then begin shimmying the helmet off, once it is past the walkers ears it should slide right off, if not then just shimmy the helmet off until it comes off.
The figures contained in the Custom Showcase are not for sale by Figure Realm, and the creators of the customs are no way affiliated with Figure Realm. The Custom Showcase is purely for entertainment purposes and only provides a means for the creators to show off their work and trade ideas. Figure Realm does not make or sell customs.