On the artboard, select the object to which you want to apply a brush. The Properties panel will display the properties for the object.

Under Brushes in the Properties panel, click Fill or Stroke, and then click one of the brush tabs: Solid color brush , Gradient brush , or Tile brush .

At this point, you can define a brush by picking a color, creating a gradient, or making a tile brush. Additionally, you can click the Brush resources  tab and apply an existing brush resource to the selected object.

Tip:

A Color eyedropper  appears in the lower-right corner of the color Editor when you modify a Solid color brush  or a gradient stop on a Gradient brush . With this eyedropper selected, you can grab a color sample from anywhere on your desktop and apply it to the selected brush. When you modify a Gradient brush , you can select the Gradient eyedropper  and drag a line across a sample of a color anywhere inside the Microsoft Expression Blend application window to apply it to the brush. You can press the ESC key at any time to cancel out of the eyedroppers.

On the artboard, select the object from which you want to remove the brush. The Properties panel will display the properties for the object.

Under Brushes in the Properties panel, select the brush property that you want to remove, and then click the No Brush  tab.

Note:
In the case of the Stroke property, you are not actually removing the stroke. For example, you may have a stroke applied that has no brush, yet the thickness of the stroke is still present.