I am drawing a rectangle, sleeping for a few milliseconds--then I want to clear the rectangle, but I can't figure out how. (The rectangle is sitting over a graphic so I can't simply cover it up with another rectangle)
graphics.DrawRectangle(p, innerRectangle)
System.Threading.Thread.Sleep(75)
Next I want to clear the rectange...
You need to redraw the graphic (or at least the part of it under the rectangle). If this is a picture box or something similar, use Invaldiate() to force a repaint.