How do I pick up bomb rocks in Endless Abyss?

I have the Rocket Fist which the game said allows you to pick up bombs, but I was never able to. I've tried punching, whistling, and walking into them, but nothing. The Pikmin don't care either. The only bombs I've found are ceiling traps and from Dirigibugs, so is the problem that I can only pick up inert bombs already on the floor?

This hasn't been a concern until now - I finally found the Doomsday Apparatus on floor 174, but it's behind poison vents, so I can't get the purples to carry it. If I can pick up even just one bomb, I can clear the way.

I have actually found that under vague and specific circumstances, purples can actually damage the vents before choking, but I can't recreate it consistently enough to entirely break one. If anyone knows a consistent way then that could work too.