A more thorough explanation:

A shelving clause is a provision in a patent-licensing contract that requires the licensee to put the patented article into commercial use within a specified time and to notify the patentee if the licensee decides to stop selling or manufacturing it. This clause is also known as an antishelving clause.

For example, if a company licenses a patent for a new technology, the shelving clause may require them to start selling products that use the technology within a year. If they fail to do so, they may lose the license or exclusivity.

Antishelving clauses are also used in trademark licenses. For instance, a company that licenses a trademark may be required to use it on their products within a certain timeframe or risk losing the license.

Overall, the shelving clause is designed to ensure that the licensee does not sit on the patent or trademark without using it, which could harm the patentee or trademark owner's business interests.