Making perfume bottles

[imraslan]

HI I am trying to make perfume bottles in pate de verre technique, I have made the model from wax an I am trying to figure out how to make in in Glass, specifically the cavity where the perfume go. If I cast it in plaster then how will i remove the plaster from inside the glass to make space (cavity) for my perfume. I do not know how to blow glass plus i need the pate de verre colors and look. Please help