Pick it all up... I leave nothing at the range i might can use... I know most all the reloaders in my area so i know who can use what... Ill sort them by size (357, 357 sig, 40S&W, etc..) and bag them for others... Odd stuff like SKS ammo and all the 22 brass goes into a recycle bucket, then to a 55 gallon drum, then to the recycle center... I financed my last handgun purchase from recycling damaged brass and 22 casings.... It buys my powder, bullets, dies.... Not to mention the cases i get and can use...
As far as not using them for competition i would disagree... If you shoot comp with Winchester brass and you find Win brass weigh it against your comp cases once they are trimmed to the same length.. If the weight is the same or close id use them...
I dont shoot comp yet with my .223 but i use LC, Win, FC, RP, military, even brass made by who i dont know.... I have yet to notice a difference by using different cases in my hunting ammo... And i strive for 1 hole groups out of my hunting ammo...