Spectroscopic analysis of the light coming from an atmosphere is a powerful tool for revealing its properties. The problem when using conventional spectroscopy for solar fluxtubes is their unresolved character: magnetic and non-magnetic regions of a plage have to be observed as a whole. With the aim of obtaining the true intensity spectrum of an unresolved tube, the authors have developed a simple method which can reconstruct the intensity generated in the magnetic component. Only observed parameters are used: intensity and circular polarization in the plage and intensity in the quiet photosphere.