How do you get suction cups to stick to shower tile?
In this regard, how do you make suction cups stick better in the shower?
Make sure both the inside of the suction cups and your window are clean and dry before application. To enhance suction and help keep the seal tight, a tiny dab of Vaseline or cooking oil may be rubbed on the rim of the cup, or dampen your fingertip with water and lightly moisten the inner rim of the suction cup.
Considering this, why do suction cups stop working?
Basically, the seal of the suction cup is not perfect, so air can gradually leak into the inside of the cup. When there is no air pressure differential holding the cup against the wall, there is no frictional force to hold it from sliding down the wall, and it will simply fall off.
A small amount of cooking oil or even petroleum jelly around the lip of the suction cup also helps the cup adhere to a surface. Apply the chosen substance to the perimeter of the cup on the side of the lip that sticks to another surface. Use as little as possible, otherwise the cup may lose its suction power.