Would you like some advice on how to clear the model display?

Hi, I’m viewing STL using C # RenderWindowControl.
I want to erase the display of the model after loading and watching the model, but I do not know how.
Would you like some advice on how to clear the model display from RenderWindowControl?

//— code to display STL model —//
// 表示させたい3Dモデルファイル
reader.SetFileName(stlOfd.FileName);
// Mapperにオブジェクトを写像する
mapper.SetInputConnection(reader.GetOutputPort());
// ActorにMapperをセットする
actor.SetMapper(mapper);
// 描画ウィンドウにActorを追加する
renderWindowControl1.RenderWindow.GetRenderers().GetFirstRenderer().AddActor(actor);