doc = this.app.getDocument();
ICommandBars commandBars = doc.getCommandBars();
ICommandItem commandItem = commandBars.find("TestToolbar", false, false);
// you need to get your own application reference for this next line...
ICommandBars commandBars = application.getDocument().getCommandBars();
UID commandID = new UID();
commandID.setValue("esriArcMapUI.GpsToolBar");
ICommandItem commandItem = commandBars.find(commandID, false, false);
if(commandItem != null){
commandItem.delete();
}