Circular References

This code will create a circular reference and these object references will never to destroyed.
This will create a memory leak.

Dim object1 As myClass 
Dim object2 As myClass 

Set object1 = New myClass 
Set object2 = New myClass 

object1.Link = object2 
object2.Link = object1 

Set object1 = New Nothing 
Set object2 = New Nothing 

Removing Orphaned Objects

more details