The hardened emulsion must be broken down and softened to remove it. The remover can be sprayed on, brushed on, or used in a solution in a dip tank. A dip tank is a container large enough to hold one or more screens, filled with a concentrated mix of ink degrader and emulsion remover. The screen tech places the screens in the solution while completing other duties. Once the screen has become diluted with the emulsion remover and the emulsion is loose, you can remove it with a high-water pressure washer. In my experience, the dip tank has proven to be the fastest, most economical way to clean screens.
If the chemistry is mixed correctly, the emulsion should clean out entirely from the mesh with ease. Emulsion remover chemistry is readily available with a wide variety of types and prices. This type of product can either come “ready for use” (RFU) or purchased as a granular mix or concentrated liquid that requires diluting. Each has its advantages.
The premix is consistent and easy to use, while the concentrates help to give the screen tech options on complicated stencils. It’s best to test options and explore what is ultimately better for the screen area. Careful measurement and calculation per screen will provide a clear advantage of one type of chemistry over another.
If the right chemicals and procedures are followed with the ink and emulsion removal, it will be rare that you have to deal with mesh stains or hazing. If part of the image is still visible on your screen after cleaning, you may have to use additional (and harsher) chemicals to remove them. The technique to remove these stains is to scrub the mesh with a haze remover, which will indeed remove the stains but also damage the screen thread and lead to weaker mesh. Consulting with the chemistry tech may be a better option. They can suggest better techniques and chemistry to avoid this step. The goal is to end up with a clean mesh with no images remaining (either emulsion or ink).