Yeah, my son suckered me into helping with the tail end of a clean-out! Here's my question; what do you guys find are the best bags? I can get all the heavy weave bags for free from a friend of mine that owns a seed farm. But the air won't blow through them so they don't work well.
On the other end of the spectrum we have the expensive flimsy bags that the air blows through nicely but they rip apart in your hands a lot when you try to move them. And a piece of something came right through the bag and nailed me. I thought I broke a rib. So what's the solution? ( Besides not helping on any more clean-outs )

Put the expensive bags into the trailer or rolloff...so you don't have to move them.

We did that and even moving them a couple feet further back in the rolloff caused rips. And anything like an unseen nail or piece of wood causes rips in the bag. I can't even imagine what would happen if we turned the machine up to full speed!

Perhaps, it is that retrofit jet propulsuion vac...

If you go to a seed dealer (try another if your friend doesn't have them) ask for old mini bulk bags. We put the cleanout bag inside the mini bulk bag. This makes them alot easier to drag across grass, concrete, stone, etc, without tears. Most seed companys have since gone to plastic boxes for stacking reasons and still have mini bulk bags sitting around. The mini bulks have a hole in the bottom where the seed comes out, this acts as your vent or relief per say.