Use the Eraser Tool in Adobe CS5 Illustrator
Adobe Creative Suite 5 (Adobe CS5) Illustrator is used to quickly remove areas of artwork as easily as you erase pixels in Photoshop, by stroking with your mouse over any shape or set of shapes.
By double-clicking the Eraser tool, you can define the diameter, angle, and roundness of your eraser. If you’re using a drawing tablet, you can even set Wacom tablet interaction parameters, such as Pressure and Tilt.
Drag the tool over the area you want to erase but you can control the tool by doing the following:
To constrain the Eraser tool to a vertical, horizontal or diagonal line, press Shift-Drag
By first creating a marquee around an area, you can erase everything inside the area. Note that new paths are automatically created along the edges of the erasure.
If you want to erase more than a single selected object, use Isolation mode to segregate grouped objects for editing. Remember that in order to enter this mode, you simply double-click a group of items. You can then use the eraser on all objects in that group at one time without disturbing the rest of your design.