Ive had a sub box stuck in my trunk for 3mo or so and I finally got it out only to find one big *** puddle under it! I seen a hole type thing in the storage compartment, someone put a hole in the bottom of that (intentionally I believe, why I dont know) and thru that I can see a hole under it going straight thru. This isnt a spot I can get to really well to patch, the car doesnt have a massive amount of rust yet (spots of surface rust thanks to it being from idaho) I have been under the car to check this one out and it's not an easy thing to get to underneath either. So how can I fix it without ripping everything apart? Has anyone used that rust stop stuff? Does it work?

Im planning to rip the carpeting out and do a fiberglass interior (as far as the trunk goes at least) so Ill have that stuff around for a while if I need it to patch this hole.