The flasks retrieved from casting need to be cooled for a certain period. In the case of plaster invested while still hot, there could be instances of fractures.

Delicate and surface-level models are left for 30 minutes. Models with prongs are left for 1 to 1.5 hours. For investments below an hour, there may be condensation on stones.

As the waiting flasks are still hot, they are first placed in a barrel filled with water to dissolve the investment partially. Subsequently, the invested flasks removed from the barrel are washed with high-pressure water until the investment is completely dissolved. The washed investments are then placed in a vibration motor immersed in zinc oil.

This duration extends until the investment on prongs and the surface is thoroughly cleaned. The cleaned items are introduced into a cyanide blasting machine, where burnt residues and soot stains on the surface are refined.

Investments cleaned in zinc oil are dried and cut with the aid of a compressor.