suction cups

I was wondering if anyones had success using a dab of silicon on their suction cups? I know magnets are prefered, but I just don't have that options ATM. Would love to hear people's experiences. Thanks!

I have four 10" zuos suction cups. They are in perfect shape, used twice. Asking $170 or best offer. If I need to ship, we'll figure something out on the pricing that works for both sides. Thank you