How can I rejuvenate the stickiness of my suction cup on my suction cup phone mount holder?

Please try the following to help rejuvenate the stickiness of the suction cup.   

How do I get the cradle feet to come out? I press the button on the back of the cradle but the feet don’t come out.

I can’t get the cradle to attach to the ball joint of the mount.

What is the best way to use the metal plates included with my magnetic mount holder?