Squeeze the juice of one lemon into a bowl. Add 1 cup of vinegar to the bowl and stir.
Submerge a sponge into the solution, then wring out the sponge so it remains damp but not dripping wet.
Wipe down the shower glass to remove the etching with long, hard strokes, working from the top of the doors downward. Rewet the sponge as often as necessary to clean the surface.
Clean the sponge in the bathroom sink, wetting and squeezing it out several times. Wet the sponge in the water, then wipe the surface again with firm pressure to remove the vinegar and lemon juice residue.
Dry the surface with a clean cloth, rubbing up from the bottom of the door in overlapping circles to catch any streams of running water.