To clear a line in iPhone

I need to clear the current line graph and replace it with a new line graph, as and when I change the month (The createLineGraph method is called each time I change the month). What happens is that, part (just part) of the previous month's graph coincides with the new line graph. I'm using CoreGraphics + Quartz2D to 开发者_Go百科create the lines. Anyone know a solution to this grating issue?

I would suggest drawing your lines on separate CALayers, that way you can just hide/remove the CALayers.