I can think of quite a few, Tiffany, but would use something untraceable to do it with!
Thank you, everyone, for your replies. The enemies in question are brambles, ivy, grass and an out of control dogwood forest!
Nettles, cleavers and dandelions I am not so bothered about as they can be cooked and eaten.
Ideally I would like to remove everything but the soil and start again from scratch!
Diesel oil.
I think that will kill anything and everything!
Won’t it contaminate the soil forever?
Yes. 
Wait until it rains really heavily for days and then dig it out. Or hire a gardener to get rid of it.
What are cleavers?!
I wage war every day against brambles they are growing everywhere. Horrid things, they are nasty & scratch too. Both myself & my gardener have tried to get rid of them but they still regrow. Decided the only thing is to keep cutting them down, they are indestructible.
I use it a lot in cooking as it is basically a Herb - but classed these days as a weed. Which is a shame as it is so useful. The seeds can be ground and used to make coffee (it is from the same genetic family), the leaves can be added to soups/stews and also used to make medicines, and the roots can be used to make a red dye.
This tells you all about it:-
Thank you, Silver Tabby 
I have never heard it called cleavers before and had no idea you could eat it!! You learn a little something every day! 
We always called it robin-run-the-hedge and have heard some people call it sticky willy. Our large hairy dog was always getting the burrs stuck to his fur. We have loads of it in the garden too, also masses of brambles, nettles, ground elder and vetch. I think the ground elder is our main pain, almost impossible to get rid of it.
You are welcome, Glanny. I think it is also known as Goose Grass in some places.
I don’t think I’ve got any old carpet 5mtr x 4mtr ;). I’ve got the plastic though and after I’ve scalped the grass, was thinking of treating it to some kind of killing agent to make sure it can’t spring up again after I’ve put the sheeting down over the winter months.
Too much like hard work - it’s a large area and would probably need a mini-digger of some sort to prevent me having a coronary. 
We did just that, but covered the area using cardboard with black plastic sheeting on top. I seem to remember we bought rolls of it. The only problem is to make sure it is effectively kept down to prevent the wind blowing it away.
We didn’t need to use any killing agent.
What planet does she reside on ?
I think I’ll see if I can find a JCB and a Flame Thrower on Amazon!
Because it is illegal for the public, that’s why!
I thought the same Judd. Do the job in no time instead of you faffing about. Only thing is, you’d probably need a small skip as well then, to dump all the turf bits in?
Quite!
Rather irresponsible of your vet to say such a thing IMO Annie, especially without even having a clue what product/chemicals were used.
No way would I let my dogs inhale that, or walk anywhere near it till it was bone dry and preferably rained on as well.