Product review (4 stars): Works great
Okay, first of all, I used to sell GD's and I didn't even realize that some of them had baffles that couldn't be removed.  So, of course, I got one.  Before I say anything else, I'm going to tell everyone who, like me, needs someone to draw them a picture, how to remove the old one.
I can't believe people actually put a new one over the foul-smelling, moldy, old one but here's how you get rid of it.  First, I cut off as much as I could with scissors, then I used a plastic utility knife that lets you let out about an inch of blade, and held it flush against the side of the opening and shaved off the leftover edge, all the way around.  Then I scrubbed every bit that I could possibly reach, while the hole was open.  Then I put GD cleaner in it overnight and supposedly cleaned it.  As described, the baffle fits perfectly.  However, this GD has always smelled bad and I have never had one before where nothing works to get rid of it.  Of course, it's better now and I can clean the baffle but I thought the problem would be solved.  One more random comment; I noticed a lot of people bragging about grinding up bones and corn cobs, etc.  Very bad move and not what GD's are meant for--even though the mfr.'s use it as a selling point so you'll spend more money.
It's bad for the plumbing, the environment and an all-around bad idea.  GD is for the residue left after you scrape your plates and pans in the garbage pail.  Just putting that out there for people who want to be responsible users.