Remvoing Neighborhood Decorations.

In theory TOOL should be able to remove those but when I tried it just now it won't allow me to click on those objects. When I put the cursor on them all I got was the pointer and a red circle with a slash through it. I'm not familiar with everything TOOL can do so maybe someone else will be able to figure out where I went wrong. Or if it's simply beyond TOOL's ability. I know I used something similar once before to delete a laptop some random sim left on a picnic table in the town square in Tartosa that kept drawing my sims to it every time they were anywhere nearby.

You can't use tool to delete stuff in the neighbourhood. You can use it to add stuff but my understating is that even if you manage to delete something that was put there by EA, the deletion is not permanent and the objects will be back when you load the game again.
I think your best bet is to cover the wrecks with some rocks or plants.