The first thing I do is a bit of trimming. You can see some fatty stuff, particularly on the bottom right of the rack on the bottom of the pic above, that I’ll trim off. Also, if there is a skirt of meat on the bone side I like to trim that off. Also, check along the edges of the racks to see if there are any small bone fragments, and if so clean those off. The last thing I do for clean up is to pull the membrane off of the bone side of each rack. The best method I’ve used is to take a butter knife to get under the membrane to start. I’ll caution you though, there are a couple layers (not sure if the bottom layer is also membrane, I don’t science) and you only want the top layer to come off so you don’t expose all of the bones. Once you’ve started the separation with the butter knife your best bet is to grip the membrane with a paper towel (it’s slipper otherwise) and hopefully pull it all off in one yank.