Tracking down an obsolete class from a RefactoringBrowser / ClassOrganizer

I have been experimenting with some metaprogramming, which left a ton of obsolete classes.
Have been able to cure most of them, except for this last one. Pointer Finder shows:

#EventManager -> EventManager class
classPool: Dictionary
#ActionMaps -> WeakIdentityKeyDictionary
a RefactoringBrowser -> IdentityDictionary
#getCompletionController -> MessageSend
receiver: ECController
model: RefactoringBrowser
classOrganizer:
subject: AnObsoleteEvoPolygonMorph class

So there appears to be a RefactoringBrowser which has classList nil, selectedEnvironment nil, etc, but which has classOrganizer with subject AnObsoleteEvoPolygonMorph.

Is there a safe way to tidy this up please?

...Stan

I've since deleted some other classes which are now obsoletes, but the original AnObsoleteEvoPolygonMorph has resolved itself and disappeared.