Suction cups are one way to hang small items and decorations on smooth surfaces such as glass, mirrors and vinyl. Some suctions cups even adhere to walls with non-porous coverings or smooth wood. Suction cups use a vacuum seal. The trick to get suction cups to hold is to provide a surface free of dust or dirt. This allows the edge of the cup to make an airtight seal for a strong hold.
Clean the surface where you are mounting the suction cups. Wash surfaces with a damp, clean cloth. Wash glass and mirrors with a window cleaner and dry thoroughly with a towel. Suctions cups will not stick to dirt or dust.
Rinse the back of the suction cup with warm water and remove any residual dust or dirt from the edges of the cup. Dry the cup thoroughly with a towel or allow it to air dry.
Wet the tip of your finger and rub your finger over the inside edge of the suction cup. The moisture helps the suction cup create a seal.
Hold the suction cup where you want to mount it, and press it against the surface. The center of the suction cup should indent inward toward the surface slightly. Hold the suction cup in place for 15 seconds.
Release the suction cup slowly. This allows the vacuum to build in the cup without breaking the seal.