5.5.4
I did this maybe it should work.
You can use:
Set Widget variable. Remove from parent. Put this variable to null. Garbage collection.
Add this widget to array. Find this widget in array. Remove from parent. Remove from array. Garbage collection.
If you created hard reference of this asset in another asset this asset must be destroyed too.
For variables and array you can use same class. User widget class to avoid hard referencing.