They aren't easy to take out or at least mine weren't. Take out the 2 screws on the back side of the shield and pipe. After that it gets rough. I used a pry bar
http://www.sears.com/shc/s/p_10153_12605_00971327000P?keyword=pry+bar and was able to pull the upper baffle out without taking the pipes off.
No such luck for the lower baffle, it was in there. For the lower I took the front/lower sheild off the carefully removed the front head pipe from the muffler, then stuck a 1/2 inch drive breaker bar down the lower pipe and tapped out the lower baffle.
The easiest way to do it is remove the pipes completely and find something long enough to tap the bottom one out if needed, or find a tool of some kind where you can just yank them out from the rear.
Some have used a bent screwdriver and coat hangers. The bar I got from sears just needed a little grinding and it fit and grabbed the area in the pipe where the screw goes. Was able to grab that and pull the top one out.
A little breakfree/WD40 won't hurt if you clean it off after you are done. Good luck, mine were a pain in the A**.