The RDF Mapping Language (RML) enables, among other formats, the mapping of tabular data as Comma-Separated Values (CSV) files to RDF graphs. Unfortunately, the widely used spreadsheet format is currently neglected by its specification and well-known implementations. Therefore, we extended one of the tools which is RML Mapper to support Microsoft Excel spreadsheet files and demonstrate its capabilities in an interactive online demo. Our approach allows to access various meta data of spreadsheet cells in typical RML maps. Some experimental features for more specific use cases are also provided. The implementation code is publicly available in a GitHub fork.