How to delete redundant Lightmass samples?

[anonymous_user_aa97fbb61 (anonymous_user_aa97fbb6)]

Hi
I have a level that shows lightmass samples, with out containing a LightmassImportanceVolume. I started Lightbuilding in that level until I decide to seperate objects into different Level, an use this Level as a container.
If I do Show-Visuailze-Show Volume Lighting Samples, I got this:

So, how do I get rid of the samples? Are they still taken into account?
Any Ideas?

Thank you

[Arnage]

When you don’t have an importance volume Unreal will try to make one for you that fits all actors. If you want to limit it to a smaller area simply add one yourself.