I prefer to spray a cleaner into the barrels as they lay flat, and then let it sit a moment.
Then, I stand them up in the trash can at the club, and scrub the heck out of them with a bronze brush.
All the crap I push out as the brush is thrust in and out, goes in the trash can. No over spray. No mess.

Any of those cleaning chemicals make a mess of latex paint in the house.

Out there doing it best I can.