Panels a) to c) show the multiple superimposed peaks that are easily detected in the CO emission lines of R Cas, V Hya, and VY CMa. Panels d) and e) show the two separate velocity components seen in the CO lines of U Ant and S Sct. These are clear evidence for detached shells around these targets. It has also been shown that R Scl (panel f)) has a detached shell. See text for further comments.