As you remove screws or other parts from the shower, keep them in the same place to avoid losing them.

After you have the screws out, you may need to wiggle or tap on the handle to get it to slide off the stem.

After you take the handle and trim plate off, you can soak it in vinegar or CLR to remove any built up grime. This will make them look new again. Shower trim plates are usually known as Escutcheon trim plates, in case you need to ask a home repair professional about your specific model.

You can purchase caulk online or from most home improvement stores.

If you are unsure how to cut the opening, ask a professional repairman. You can also research how to cut a hole safely and easily into your wall’s material on a verified home improvement site. The hole should be small enough that you can still cover it with the handle and trim plate later on. Use the trim plate as a guide for the maximum size of your trim plate.

If your valve clip is not damaged, you should be able to reuse it while securing the new cartridge in place. If it is, however, your new cartridge should come with its own valve clip. Some valve sets are secured with a retainer nut that holds them in place. To remove the nut, hold the valve while you unscrew the nut with a wrench. You can then proceed with removing your valve.

While needlenose pliers can be used for this step, it may be easier with thicker pliers. It’s also a good idea to spray it with WD 40. Wait a few minutes, then it should slide out more easily. This will reduce the risk of damaging the valve.

If your valve cartridge will not slide into the wall or seems too small for the slot, you may have bought the wrong size. Double-check the valve size and model to make sure it matches your old cartridge. If you notice severe rust and corrosion while changing the shower valve, then you may need to change out the entire tub and shower valve assembly.

Do this slowly. If something wasn’t installed correctly, you won’t want the leak to burst with water. [7] X Expert Source Dave JonesMaster Plumber, Roto-Rooter Plumbing & Water Cleanup Expert Interview. 29 March 2021.

If you enlarged the wall opening earlier, you should be able to put everything back in place so long as the hole is not larger than the trim plate. Fill the hole back in if you accidentally made it too large.