Set object's origin to world 0,0,0

I have a certain number of objects whose origin I want to all be set at the world’s (0,0,0) coordinate. I can’t figure out how to do that. Any suggestions?

alt+g is for clearing location.

also,
alt+r for clearing rotation
alt+s for clearing scale

Maybe there are easier ways, but I would just put the 3d cursor at the origin (for example using the View Properties window), then for all objects do Center Cursor (in the Object menu, under Transform).

View Properties is what I needed, thanks abelabel!
Alt+G, yes it gets the object’s origin to (0,0,0) but it also moves the object which was undesirable for what I was trying to do. But thanks anyway, Minifig