Wits and Hefes normally almost are almost always unfiltered, so they're excellent candidates for yeast harvesting.
I left a bit of beer in each bottle as I finished it (for the sake of doing it right I had to kill the 6'er all in the same evening
), then swirled/shook the bottles around to break up the sediment from the bottom of the bottle. That was a number of months ago and I can't recall the exact amounts of water and DME that I used when I did it.
From there it all went into a very small starter wort that I stepped up with more wort about every 3 days until it looked like my other startes do after 3 days when made with yeast from White Labs.