No sheath yet. I've experimented with a few methods but haven't found one that works for me yet. The antique needles came in several lots, the first lot as a bagful from the thrift shop and the rest from eBay. Once (out of about 20 purchases) the needles were actually the same size as the label on the container.{*} I have several gauges I use to sort the random bunches of unsorted needles into sets, one of which is a wire gauge that was made in India and includes some unusually small sizes. It's very helpful for sorting the in-between sizes of tiny needles.
The Boye brand tips have a nice taper without being so sharp that they draw blood. The totally blunt needles are hard to use even with firmly twisted thread. Generally, the more similar the tip is to the Boye standard, the better I like it, but there are lots of variations.
{*} I'm not complaining; there's no reason that an eBay seller should spend $20 or more to buy gauges just to measure needles they'll sell for $10 or so. I've become rather good at guessing what gauge a piece of wire is from what it's next to in an eBay photo. :-)
=Tamar