This might help a bit. In the photo from the left: M34 WP body, BLU-17/ submunition with special long spoon with slots for retainer band, M15 grenade body, and two other WWII vintage M15 varients.
You can see the BLU-17 body is slightly longer and larger in diameter than the hand grenades. It is also more "square" looking with smaller corner radii, especially at the bottom. This example also has the demil punch hole like the one Fragman has. As far as I know, these came from a scrap yard in Indiana that purchased them as steel scrap from the Crane Naval Ammunition Depot. I picked out 20 or 25 of them and am aware of a couple of dealers who bought more than that.
All of the items in this particular pile of scrap were originally white phosphorus filled and all were demilled the same way with a punched hole to allow the WP to burn out in a furnace. As you would expect, no paint remained on anything, just rusty steel. I got the impression it was more a random clean up of odd items from storage rather than a large, organized demil program.
While there were fairly large quantities (perhaps a few dozen of each) of M34 grenade bodies and BLU-17s, there were also very small quantities of several other pieces, maybe 1 to 10 of each. These included M57 81mm mortar bodies, M123 napalm bomb bursters, 57mm recoilless rifle projectiles, and a few other odd bits.
