How to clear a background layer

General
1
  1. If nothing is loaded in background layer with loadbg command then play command will have no effect.
  2. If we have loaded something in background layer with loadbg command, it will play in foreground layer with play command.
  3. If we send loadbg 1-1 empty again it will clear foreground layer when we send play 1-1 command.

What command should i send to achieve 1st condition if i have issued loadbg command already?
Or
I think there is no command to do it then What is workaround to achieve it?

2

Use RESUME instead of PLAY.