Don’t worry, it’s not as gross as it sounds. As described in an earlier post, trademark rights in the United States are based on use of a mark in commerce in connection with particular goods and/or services. Also unlike most foreign countries, the US requires proof of use of to federally register a trademark (except in limited circumstances), although the mark need not be in use prior to filing an application. This evidence of use is what is commonly referred to as a “Specimen of Use.”
What constitutes an acceptable specimen depends on whether registration of a mark is sought in connection with use on goods or use in connection with services. In an application to register goods, the USPTO generally requires that the mark be used on the goods or their packaging, or on tags/labels affixed to the goods. In an application to register services, the USPTO generally requires use of the mark on materials advertising the service or provided during the sale of the service.
The foregoing is not an exhaustive list of what constitutes an acceptable specimen. In reality, what constitutes an acceptable specimen (or doesn’t) is highly fact-dependent, and it is recommended that an experienced trademark attorney be consulted before providing proof of use to the USPTO.