You can delete all the keyframes from selected layers, or simply delete one layer or multiple layers at a time.
You can select multiple layers at a time by Ctrl-clicking each one or by Shift-clicking a range of layers.
Select the layer or layers with keys you want to delete.
Right-click one of the selected layers, then select Clear Animation on Layer from the context menu.
The layers no longer contain animation.
Select the layer you want to delete. You can also Ctrl-click to select multiple layers.
Click the Delete button in the Animation Layer editor toolbar.
You can also right-click on one of the selected layers and select Delete from the context menu.
All selected layers are removed from the scene.