Spray a mixture of 1 part mineral oil and 4 parts water onto shower doors, and wipe it off with a sponge. Remove soap scum with 1 cup of liquid fabric softener diluted in 1 quart of warm water. Spray it onto the shower doors, and rinse with warm water.
A natural method of cleaning shower doors is to cut a lemon in half, dip it in baking soda and rub it on the glass. After rinsing the shower door, apply lemon oil to the clean glass to repel water and prevent soap from adhering to the glass.
A do-it-yourself shower spray of 1 cup of water, 1/2 cup of vinegar, a squirt of dish soap and 10 drops of essential oil inhibits soap residue build-up. Spray this mixture after the glass has dried.