The NuSTAR mission performed a long (200 ks) observation of the Arches stellar cluster in 2015. The emission from the cluster represents a mixture of bright thermal (kT~2 keV) X-rays and the extended non-thermal radiation of the molecular cloud around the cluster. In this work we describe the method used to decouple spatially confused emission of the stellar cluster and the molecular cloud in the NuSTAR data.