Coop them in an area away from the plastic or nails is your best bet. Or if they are stubborn enough to eat plastic and nails natural selection will keep the wise ones around and get rid of the foolish.
I run a magnet around every year, and OFTEN if any work has been done outside. Amazing what turns up! It's about cleaning everything up, and keeping them out of bad areas. I think that you could rent one of those magnets on rollers.
Mine too. Instead of MarsAtHome, I should have registered PostApocalypticFarming!
It's like eating an elephant though... one bite at a time. If you garden and make compost and whatnot, you should have some soil screens (also good for mealworm farming I guess). What I've had to do is till, dig, shovel, sift (coarse), sift again (med), and sift even more (fines). Not perfect and certainly labor intensive but it is the only way to be comfortable in the space.
While I'm at it I mix in coco coir, and whatever other enhancements I need. Basically a nuclear option, but it is what it is.
Oh, I should mention that I only work a square yard or two at a time, to about a foot deep. Do that in a different spot each weekend, focusing on the spots you want to recover first.