I read once to use emery sand to keep the needles sharp, but I could never find a source for it, and I read somewhere else to use cut up or pressed together wool because wool has lanolin and it keeps the needles lubricated and the rust away. Any truth to any of this? My nephew is allergic to tree nuts, so walnut shells are a no no for me. I used the wool option this time to keep the pincushion lightweight, but at the same time, I don't know if it is true that it will keep the needles lubricated and rust free. Hugs all.