I got the same problem, though mines not very rusty.. It broke off when some kids in an Aztec cut me off in a blizzard, and i swerved and slid part way in a ditch. This was whe3n my tires were bald so i thought for sure I was stuck, but luckily the tires decided to work and get me out lol. And then after that the rattling began.
I still gotta drive it on some ramps, and stick a screw or two in it. I was going to do it when my brother changed my oil(I was going to do it, but he offered lol) but he drove it off the ramps when i brought the screw out..And I hate driving up ramps(always feel like Im going to jump them lol)
Everyone i talked to said either Repair it(putting new screw in it) or replace it, either or, but it needs to stay on.