Space in trunk by the fenders - trash

I just finished my trunk, and floor pans; learned a lot.
If you lay under the car, at the rockers and quarters, you see that the floor/trunk connect to the body, with a wavey bend about every 8".
That's for water to exit, but road spray fills them up. Get a welding rod, and poke in them, using vac and air pressure, from the inside,- you will make your car 4# lighter, and rust problems go away.