Propolis is sticky at room temperature but it becomes brittle at lower temperatures. Bees will efficiently propolise anything smaller than a bee space. This clever product exploits these two facts to allow you to collect propolis from your hive.

The propolis mat sits under the lid. The raised parts of the propolis mat make bee space between the frames and the mat. Once the mat is full of propolis, you can freeze it and crack the propolis off. Autumn is the peak time for propolis production. 

You may find that you have better results if you stick a match stick between the mat and the lid.