According to today’s practice, wood waste is roughly classified into three or four classes, depending on the country. The most polluted grade, often referred to as grade C or AIII/AIV, consists of preservative-treated wood, i.e. wood that has been impregnated with chemicals (pesticides, biocides and fungicides) to enhance its bio-resistance. Grade C or AIII/AIV is not currently recycled. The increased use of wood as encouraged by initiatives like the New European Bauhaus is likely to require additional volumes of preservative-treated wood. Even though such treatments extend the service life of wood products, they will still eventually become waste and must be dealt with. Wood preservation compounds pose a significant threat to not only the environment but also to human health, and therefore it is needed to develop efficient remediation technologies. At the same time, current recycling processes are greatly complicated by the presence of pollutants (chemical treatment products, heavy metals), which calls for further research on cleaning methods. As grade C comprises of several types of wood types and products, along with different levels of contamination, this poses a complex problem that needs action from both the circular economy and non-toxic environment fields. The development of an automated on-line characterization system to distinguish chemically contaminated wood waste has become a high priority. Gaps in existing regulations should be considered as may not fully support the use of upcycled wood materials from such waste streams. IN2WOOD proposes a multi-dimensional cascade approach for highly polluted post-consumer wood waste via a series of seven Pilot Validation Trials (PVTs) with aim to reduce the demand for virgin materials, reduce unsustainable options such as landfilling or incineration, and support the transition towards a circular economy by developing new value-added products from clean secondary materials.