Why do you need the shelf for this? I can do the same thing with the comma trick. Find a file you want to move, press comma, lather, rinse, repeat. Then perform the action on all the files at once.*

My understanding of the shelf (which I also do not use very much) is that it's for keeping frequently used information handy. That snippet of code you seem to use a thousand times a day. Text of an email you send regularly. (but why aren't you using mailtemplate?) I haven't ever found much use for it. I suppose it could save me a lot of time in writing code if I ever thought to use it. I'm sure it will come in handy when I begin my computer science program.

*I noticed this was working from the Finder. In which case I would use CMD+OPT+/ (Quicksilver with selection) for each item or group of items. It works with multiple selection. It's slightly annoying that when you use the selection, the QS window opens up with the action pane selected. So, you have to tab back to the items pane. No big deal though. It's also worth noting that when you comma trick a multiple selection, it appears as just one item in the holding tank for comma tricked items.