Volcanic ash (VA) from Mt. Etna, frequently deposited in surrounding urban areas due to intense eruptive activity, poses significant environmental, infrastructural, and economic challenges, especially related to cleanup operations and air traffic disruption. Traditionally treated as waste and destined for landfilling, VA management has been reconsidered in light of Italian Law 108/2021, which promotes its reuse within a circular economy framework. The REUCET Project developed technical Guidelines for the recovery and reuse of VA from Mt. Etna in various civil and environmental engineering applications. The proposed applications include its use as a raw material in cement and mortar production, lightweight ceramics, road foundation layers, and in the development of innovative materials for air and water treatment. These include photocatalytic composites and zeolites, derived from the fine ash fraction (<1 mm). Recovery processes require preliminary screening to remove contaminants and classify VA by grain size, a key factor for its integration into suitable production cycles. The Guidelines aim to enable sustainable and economically viable VA reuse while ensuring environmental and public health protection.