I ran them for quite a while. I don't like the small micron felt socks you usually see though, they clog extremely fast, are tough to clean, and the felt falls apart fairly quickly. I used nylon mesh socks with a 300 micron rating. It would pull out excess foods and pieces of Nori that got sucked into the overflow, but let tiny particles through that my skimmer would pull out. These are pretty much uncloggable...

For cleaning I would simply pull them out, turn them inside out and spray all the crap out then let them dry. They would look brand new and no need to use them in the washer, etc.

It really depends on the system and the reefer who maintains the reef if they want to use them. There are great reasons to use them, and just as many not to.