If your shower doors are caked with soap scum, you may already have discovered it is easier to prevent soap scum than to remove it. Removing soap scum takes a lot of elbow grease, especially if the soap scum has been building up over a long time. There are a variety of methods you can use try to remove soap scum. Do not give up if one method does not work to get the soap scum off your doors. Instead, just move on to the next method and see if it leaves your shower doors sparkling clean.
Slice a lemon in half and rub the halves over the scummy doors. Let it sit for a couple of minutes. Rinse with water to see if it removed the soap scum.
Make a paste with baking soda or powder washing powder and some warm water. Use an acrylic scrubber in a circular motion to clean the soap scum with the paste. Rinse with warm water.
Put on plastic gloves and use an acrylic scrubber to apply to your shower doors either straight vinegar with a little salt or some diluted ammonia. If using the ammonia, dilute ½ cup of ammonia in a gallon of water. Remember to apply in a circular motion for best results. Rinse well with water.
You can prevent soap scum by periodically applying lemon furniture oil to your shower door with a soft cloth.