From My experience As already mentioned, they do need reasealed, or at atleast of couple of wax coats at a minimum. Shaft sealer Is usually enough to do It. With these type of materials even the dust from turning the tip can stain them. I almost always have to clean these types of materials before sealing, no matter how well I keep the dust off when working it, some will make It back on to the ferrule. after cleaned, sometimes I can kind of burmish the ferrule as you would the tip, and helps alittle.
Also as mentioned as well, some do have impurities embedded in the material, but does not seem to effect the play any.
I also make several slow smooth passes on My cuts, I usually start as far as half way from My destination, and sometimes even farther then that, this might be taken It overboard to some, but since I started doing It this way, My final cuts are almost always perfect, don't need hand worked much, and keeps any high sides to the bare minimum. I am starting to do all my tenons this way as well, and think I am going to stick with it. Time is Money, and I guess some might prefer to chop down closer to the destination first before making finals, But IMO It saves me Work down the line, and produced a cleaner final product. This seems to be especially true when turning metals. On the few cues I am building nearing completion now, I even went as far as turning the tenons down as if they were shafts or butts, allowing time for movement in the wood in between passes. I know that was really extreme, but only did It on 4 cues, and time was not an issue really at that time, Just wanted to see the end result. Gotta feeling I am going to like It, from how true the blanks ran right after glue up, even before first cuts to mate the forearm & handle. Greg