A technique for mapping spectral line sources using closure phase VLBI techniques is described, and some initial results on circumstellar shell sources are presented. The maps show an unresolved point source on the nearside of the shell, but no corresponding source on the far-side of the shell. This is interpreted in terms of amplification of the stellar thermal emission. Preliminary results are also presented on another source, OH17.7, which show correlated flux outside the velocity range of the known OH masers, and it is suggested that this represents high velocity (~600 km s−1) violent motions around the central star. If confirmed, this may represent a new class of source, representing violent phenomena associated with red giant stars.