The Best Way to Make Suction Cups Stick to a Window

Suction cups offer a solution for attaching sun catchers, bird feeders and other useful and decorative objects to windows without harm to the glass. Suction cups stick to the glass on the outside or inside. Car accessories such as PDA holders, cell phone mounts, notepads and other handy items stick to car windshields via suction cups. To prevent stained glass artwork or crystals from falling, mount suction cups securely. In minutes, you can improve a suction cup's seal.

Suction cups hold decor on windows.

Cleaning is Crucial

To assure a successful suction cup seal, one of the most effective tactics is to start with a quality suction cup. Both the suction cup and the window must be squeaky clean. A suction cup covered with grit, dust or grease will not adhere strongly. Assuring that the suction cup is clean involves a quick wash in warm soapy water. Rinsing the suction cup well removes any soap residue. White vinegar in water provides an inexpensive and eco-friendly window-washing solution. By avoiding chemical window cleaners you protect the suction cup from damaging chemicals.

Seal Secrets

Suction cups perform well with warmth. Getting the initial seal tight involves timing the application for a warm part of the day or using a blow dryer to warm the glass. Wild Birds Unlimited recommends using a little skin oil on the suction cup by rubbing some from the face onto the inside of the suction cup. The idea is that saliva and water evaporate, whereas a bit of skin oil will remain in place. Cooking oil can be used as well. The site also points out that the quality of suction cup makes all the difference. Inexpensive, small, shallow suction cups don't have the sticking power of larger, high-quality cups.


Suction cups can degrade or warp over time, especially if exposed to heat or the elements. Replace suction cups that no longer adhere securely. Check hardware and crafts stores for replacement suction cups. Inspect suction cups that are in use every two months and press out any air. When the cup loses its seal, air seeps in. Use fishing line to hang stained glass, crystals and other decorative items from suction cups to create an effect of the art being suspended over the glass.