The problem is the brass will be dirty and full of dirt. Plus its not easy to get the junk seperate from the brass easily.
If you have a range with enough brass on the ground to have a "brass party" its obvious members are not interested.
i would always go down to the range after a "shoot/training" they always left brass.
i have cleaned up the first 4' or so in front of the line.
Methods where various.
we used those construction magnets with wheels to get the steel.
I used a modified clam rake buy lining it with some 1/4" screen. This helped in getting into the sand a few inches. All was good when there was free time to do such a thing. One member had that spring steel wheel that worked pretty good.
Maybe consider one of these
ammoupusa.com
The time and effort put into the clean up is hard to recoupe. If you want to sell the brass for reloading you have to sort it and not have it full of junk.
You want to recycle it. Well the yards will not give you top price if cases are full of dirt and rocks.
Turning In your brass and steel for scrap if they will take it is the easiest quickest and more than likely the best return for your time and labor.
now the best time to try to recover brass or lead from the range is late spring early summer. When the ground dries out quickly.
Depending on how fast it dries.....about 3-4 days after a nice heavy down poor. The soil will be looser and the newer brass on the surface will show more.
I cashed in my junk in spring
CLEAN ammo brass $1.72/lb
CLEAN steel ammo case .03 cents lb. If you have 100lbs or more they gave .05/lb
Last i checked local place was paying .82/lb for brass and they where rejecting small lots of scrap steel.