Optical and IR data (black points) of SMC and LMC sources classified as post-AGB stars with a shell-like structure by K14 and K15, which we interpret as surrounded by carbonaceous dust in the present investigation. The grey line in the middle panel of the bottom line shows the IR spectroscopy results from Volk et al. (2011). The red lines indicate the best-fit model obtained by the DUSTY code. The derived stellar and dust parameters for each source are shown in the different panels.