The data map in hudson.diagnosis.OldDataMonitor keeps growing on my machine.

I have removed an old plugin, which has stored it's settings in all project files.

Now, on each load/access of a project a new FreeStyleProject object seems to be created and each time the old data is found and the project (as it is a Saveable) is stored as containing old data in the data map of the OldDataMonitor instance.
One would think that this should not be a problem with only 20 projects but FreeStyleProject does not implement equals and hashCode and therefore every single project object is kept around in this map.
After a week since the last restart it has accumulated a total of over 200k map entries totaling a whopping 1GB of heap memory.

I would love to remove this old data but because of bug JENKINS-18809 I can't even do that. I will remove it by hand.