SBJ needle insert--removable??

Hi folks,
 I think I know what the answer to this question will be, but I'm gonna ask anyway! Has anyone tried to remove and re-fit the threaded insert for the needle in the tank backplate on a Space Bug Junior? The reason I ask is that on my SBJ the insert is visibly dirty or rusty through the clear-ish nylon, and looks terrible. I am going to experiment with my ultrasonic cleaner to see if it will shift the crud, but I'm not holding my breath waiting for that to be successful. I would guess the insert is pressed in, not moulded in, but how tight is it? I don't mind being the first to try it, but if someone already has, so much the better; after all, it's said that it's smart to learn from your mistakes--so learning from someone else's has to be even smarter, right?