Cautious recyclers
Pax--the only thing recyclers have ever been dicey with me on is, "Are you SURE there isn't any live ammo in all these??"
1 or 2 places in my area won't take fired brass at all for the above reason--this is America, this is capitalism, OK, I just go to places that do take brass.
If there were a question about spent primers in or out, I'd check VERY carefully to make sure that removing the primers would be worth my while. Depriming thousands of cases would be a hassle unless it honestly paid $$ to do so. Jack Of All Trades, above, has the best method IF you find that it'll pay.
If there is a market in your area for once-fired brass to shooters, they'll pay more than for scrap. The trick is finding that market. Again, sorting all yr range pick-ups to find the salable ones is a hassle; make sure it pays to do it before going to the trouble. The belted magnums especially might be worth it; some of those cases cost more than $1/ea, new.
Any road, you have some $$ sitting there, even if the brass is nothing but scrap. I fail to see a downside to this.