I'm curious as to why ammonia? I've done lots of automotive window tinting, and there we AVOID anything ammonia like the plague, unless you are removing tint. ammonia does a great job of eating away at adhesive. (want to remove a dealer decal from your car? spray windex on, then cover it with saran wrap and tape it down, it will fall off in the morning)

anyway, anyone try a couple drops of dishsoap with water? that is a favorite for tinting.