If you have a 4" coil it is perfect for this.
They are pretty cheap to buy aftermarket if you need one.
I use the 8" in some tot lots when I come across them swinging my F2, because I am too lazy to change it, most times.
A trick is turn down the sense, you should still get good depth, and swing slow near big metal.
If there is a target near a post you should still hear a telltale double beep.
Patton says moving slow from further away straight in to the post will also work.
Still listen for that double beep.
This works better on my Compadre, but I have had success with the F2 and the large coil with this technique, too.
Also, don't use disc in tot lots.
I picked up a clasp from a thin chain in the chips and the chain itself was jumpy, but the clasp came in as a solid 06 iron which is why I found it.
Really small gold might come in as iron, too