After you have coated your screen with photo emulsion, exposed the screen, screen printed with the screen, and then cleaned it, you may want to remove the photo emulsion so you can reuse the screen.
I had read that you can use bleach. So I bought a gallon of bleach for a dollar at the local grocery store. After I had washed away the leftover ink using warm water, I brushed on bleach, and let it sit for a while, and scrubbed it with a nylon bristle brush. Then I sprayed the screen with warm water. Some of the emulsion had been removed. I reapplied the bleach, scrubbed, waited, sprayed, and more came off. After about four applications, the screen was pretty much cleared. Basically, it was a lot of work, and used a lot of bleach.
I decided to try stencil remover. The local art supply store was out, so I drove to Syracuse, and bought some over there (combining the trip with a book hunting expedition). The quart bottle was relatively more expensive than bleach. I hoped it worked.
I poured just a little of the stencil remover on the screen, and used the nylon bristle paint brush to spread it around, I scrubbed lightly with a nylon bristle scrub brush, and then wait a few minutes. When I sprayed the screen, almost all of the emulsion was removed. Just a dab more stencil remover, and the rest was gone too. Compared to bleach, this stuff was magic.
The stencil remover hands down beat the bleach. I have also read that bleach is harsher on the screens, and will shorten their life. As the old saying goes, use the right tool for the job.