How to move a layer from the default tray to a second tray

My default tray has become overpopulated and way too long with items I probably won’t use again, but who knows.
I’d like to move those layers to a new tray, where they will be available should I need them, but my default tray will be freed up.
Is this possible?

Your post is confusing but it sounds like you want to have two different Layers panels one in each of two different trays. The thing is, there is only one Layers panel. You can have it in the Default tray or in another tray but you can’t have two Layers panels at once.

Thanks DaveR.
I’ll try deleting the probably-not-needed-again geometry to a second SU model.